doctor examining woman's shoulder

If you’ve ever had to deal with an achy — or downright painful — shoulder, you’re not alone. According to a 2011 paper published in BMC Musculoskeletal Disorders, 70% of individuals will visit a primary care doctor because of shoulder pain at some point in their lifetime. Shoulder pain can be persistent and tricky to resolve. An estimated 40%–50% of patients with shoulder pain still have pain a year after first seeking treatment, and 25% of people currently dealing with shoulder pain have had similar episodes in the past.

Shoulder anatomy is complex, and while that makes it one of the most mobile joints in the human body, it also means there are plenty of ways things can go wrong. Problems with the bones, connective tissues, muscles, and nerves in and around the shoulder can all lead to pain. Inflammation, traumatic injury, overuse, and old age can seriously damage the joint and make certain movements extremely painful or even impossible. Treatments are tailored to the underlying cause, but doctors generally like to start with conservative measures such as physical therapy, activity changes, and pain medication before opting for more invasive options. However, in some cases, surgery or even a total joint replacement is necessary to alleviate pain and restore mobility (via Orthoinfo).

Shoulder anatomy

x-ray of shoulder

To better understand the many causes of shoulder pain, you first need to know a bit about the anatomy of this complex joint.

Although most people think of the shoulder as a single joint, it’s actually two (via Verywell Health). The glenohumeral joint is a ball-and-socket joint that connects the top of the arm bone (humerus) and the shoulder blade (scapula). Most shoulder movement happens at the glenohumeral joint. The acromioclavicular joint connects another part of the scapula and the collarbone (clavicle). The joint capsule surrounds the ball-and-socket of the shoulder and is filled with fluid that provides cushioning. The glenohumeral joint is also surrounded by a rim of cartilage called the labrum, which gives the socket part of the joint more depth and therefore more stability. There are also several ligaments that connect the bones of the shoulder joint directly to one another.

Surrounding the glenohumeral joint of the shoulder is the rotator cuff, a group of four small muscles and the tendons that attach them to the bones of the shoulder. The rotator cuff stabilizes the joint and allows for its wide array of movements. There are, however, 13 other muscles that cross or attach to the shoulder joint, and problems with any one of these can cause issues with shoulder alignment and movement, leading to pain.

Broken shoulder

man in shoulder sling talking to doctor

The shoulder is made up of three bones (the humerus, scapula, and clavicle) and, under enough pressure, any of these may break. Falls, sprots injuries, and car accidents are the most common causes of a shoulder fracture.

According to Penn Medicine, shoulder fractures can be divided into two types: non-displaced and displaced. Non-displaced fractures, in which the broken bone or bones stay in place, make up about 80% of all shoulder fractures. By contrast, in a displaced fracture the bones move out of their normal position and need to be realigned. Because the bones shift, displaced fractures can also result in other damage to the shoulder, such as tearing of the rotator cuff. Symptoms of a broken shoulder include pain, swelling, bruising, redness, and joint instability. The shoulder may also visibly appear out of place or deformed.

Very little intervention is needed for most non-displaced fractures. A sling keeps the shoulder immobilized while the bones knit back together. This process takes about six weeks. For displaced fractures, however, surgery may be needed to realign the bones and fix them together with pins or plates. Surgery may also be needed to repair other shoulder damage done when the bones broke. Rehabilitation therapy is usually needed after surgery to ensure the healing shoulder retains good range of motion (via the Cleveland Clinic).

According to Healthgrades, the clavicle is one of the most commonly broken bones in the body, particularly among children and teens and those who play sports.

Dislocated shoulder

doctor manipulating woman's shoulder and arm

The shoulder is a ball-and-socket joint, and if the ball comes out of the socket, it’s known as a dislocation (via the Cleveland Clinic). Because the shoulder is the most mobile joint in the body and the socket is quite shallow, the shoulder is the most commonly dislocated joint.

Dislocations are usually caused by falls or a blow to the shoulder. Symptoms of a shoulder dislocation include extreme pain, swelling, bruising or redness, muscle spasms, numbness or tingling in the arm or hand, and difficulty or inability to move the arm. In some cases, you may be able to actually see that the ball of the joint is no longer in the socket.

It’s very important not to try to reset a dislocated shoulder yourself, as this can damage blood vessels, nerves, muscles, and other tissues. Move the joint as little as possible and seek immediate medical attention. Once a dislocation is officially diagnosed (usually using x-rays or other imaging), the doctor will carefully reset the joint into proper alignment. This may need to be done under sedation, because it can be extremely painful. Once the shoulder is back in place, however, severe pain stops almost immediately. Often, the ligaments, tendons, muscles, and labrum surrounding the joint are damaged during a dislocation. After a shoulder has dislocated once, it’s less stable and more likely to dislocate again. If a shoulder keeps dislocating, surgery may be needed to stabilize the joint.

Frozen shoulder

woman holding her right shoulder

Also known as adhesive capsulitis, frozen shoulder is a condition in which the capsule of connective tissue that surrounds the bones, ligaments, and tendons of the shoulder joint thickens and tightens around the joint (via the Mayo Clinic). This makes normal movement difficult. Frozen shoulder develops gradually and follows a three-stage pattern. In the first stage, the shoulder’s range of motion starts to decrease and any movement of the joint causes pain. In the second stage, moving the shoulder becomes even more difficult as the joint stiffens, although pain may actually decrease. In the final stage, range of motion slowly returns. The whole process usually takes one to three years.

Although doctors know that frozen shoulder is caused by a thickening and tightening of the joint capsule, it’s still unclear why this happens. Women over 40, individuals who’ve recently had their shoulder immobilized for a long period of time (for example, because of a shoulder injury), and those with certain chronic health conditions (including diabetes and heart disease) are at increased risk for frozen shoulder.

Over-the-counter and prescription pain relievers and anti-inflammatory drugs can help manage the pain of frozen shoulder. In some cases, corticosteroid injections into the joint may also help with pain. Physical therapy is key to maintaining as much range of motion as possible. In some cases, doctors may inject saline into the joint to stretch it or manipulate the joint while the patient is under general anesthesia in order to help loosen it up.

Rotator cuff tear

multiple scans of an injured shoulder

The four muscles of the rotator cuff are the supraspinatus, infraspinatus, teres minor, and subscapularis (via Orthoinfo). They’re attached to the head of the humerus by four tendons. If one or more of these tendons tears, it can cause pain and make moving the shoulder very difficult. Most tears happen in the supraspinatus tendon. Rotator cuff tears are very common; each year, around 2 million Americans visit the doctor because of a rotator cuff injury.

A rotator cuff tendon tear may be a partial tear (in which the tendon frays but doesn’t completely tear) or a full-thickness tear (in which the tendon separates from the bone). Most rotator cuff tears happen slowly over time because of repeated stress on the tendon. But falls, improperly lifting something heavy, and other injuries can cause an acute tear. Acute tears usually cause intense pain and an audible snapping noise. A tendon tear that develops slowly tends to cause mild pain that gradually worsens over time.

Initially, pain may only be present when doing certain motions (such as lifting the arm overhead), but as the tear worsens, pain may be noticeable even at rest. For about 80% of individuals with a tendon tear, nonsurgical treatments such as rest, icing, NSAIDs, and physical therapy can relieve pain and improve shoulder function. Surgery to reattach a torn tendon to the humerus may be needed if the tear is large and pain can’t be controlled with nonsurgical treatments.

Shoulder sprain

man holding shoulder in pain

A sprain occurs when a ligament — tough connective tissue that connects bones to other bones — is stretched or torn (via Harvard Health). Although ankles are probably the most notorious site for a sprain, sprains can happen anywhere there are ligaments, including the shoulder. A shoulder sprain is also known as a shoulder separation. Shoulder sprains are most likely to happen at the acromioclavicular joint, where the collarbone and the acromion (the top front part of the scapula) meet. More uncommon is a sprain where the clavicle meets the breastbone (the sternoclavicular joint).

Shoulder sprains can happen as the result of direct injury to the shoulder (such as a car accident) or from falling on an outstretched arm. Shoulder sprains are classified based on their severity (per NYU Langone Health). In a grade 1 sprain, the ligaments stretch or partially tear, but the bones don’t separate from one another. Pain and swelling are usually mild. Ligaments tear in a grade 2 sprain, causing higher levels of pain and swelling. In a grade 3 sprain, the collarbone separates from the acromion, causing a dislocation. In the most severe types of sprains (grades 4, 5, and 6), ligaments tear, the collarbone dislocates, and muscles are torn from the collarbone.

Grade 1 and 2 sprains are usually treated with rest, ice, anti-inflammatory drugs, and the use of a sling. More severe sprains, however, may require surgery to realign the collarbone and repair damaged tissues (via Advanced Orthopedics & Sports Medicine).

Torn labrum

physical therapist helping man with shoulder exercises

The labrum is a cup-shaped rim of cartilage that lines the ball-and-socket joint of the shoulder. It provides stability to the shoulder both by increasing the depth of the socket and by serving as an attachment point for the shoulder ligaments. A tear in this cartilage can cause aching pain, instability, and a grinding, catching, or locking feeling when moving the shoulder (via the Hospital for Special Surgery).

There are two main types of labral tears. A SLAP (superior labrum from anterior to posterior) tear occurs at the front of the upper arm where the biceps tendon attaches to the shoulder. As a result, people with SLAP tears feel pain at the front of their shoulder. Bankart tears, on the other hand, occur during a shoulder dislocation. When the ball of the shoulder slips out of the socket, the surrounding joint capsule pulls on the lower portion of the labrum and tears it. This labral tear makes it more likely for the joint to dislocate in the future. Athletes in particular sports, including baseball and volleyball, are most likely to experience a labral tear, although falls or other forms of trauma can also cause them.

Some labral tears, especially SLAP tears, may heal on their own with the aid of rest, anti-inflammatory drugs or injections, and physical therapy. If the tear is severe or gets worse over time, surgery may be needed to reattach the labrum to the bone.

Impingement

woman holding shoulder in pain

In shoulder impingement syndrome, the top outer edge of the shoulder blade (the acromion) rubs against or pinches the rotator cuff tendon beneath it (via the Cleveland Clinic). This causes inflammation and swelling of the tendon, which makes the already narrow space the tendon must operate in even narrower. This leads to even more rubbing against the acromion, creating more inflammation and swelling. It’s a vicious cycle that’s all too common. In fact, 44%–65% of shoulder pain complaints are caused by impingement.

Impingement pain usually develops gradually over weeks or months. Positions that are most likely to cause pain include having the arms extended overhead, lifting or lowering the arm, and reaching behind the back. Pain is usually felt in the front of the shoulder, and is usually worse when laying on that side. The shoulder may also feel weak or stiff. Treatments for shoulder impingement focus on reducing inflammation and pain and restoring range of motion. Rest, ice, anti-inflammatory drugs, corticosteroid injections, and physical therapy can all be helpful. In some cases, subacromial decompression surgery is needed, in which doctors remove small pieces of the acromion to create more space for the rotator cuff tendon.

Although impingement can be caused by unlucky anatomy (a particularly narrow space beneath the acromion), impingement is often precipitated by other shoulder conditions (such as rotator cuff tendonitis or bursitis) that create the initial inflammation that eventually snowballs into impingement.

Bursitis

woman applying ice to shoulder

Throughout the body, thin, sac-like structures called bursa help reduce friction between bones and softer tissues such as ligaments and tendons (per Johns Hopkins Medicine). If subjected to too much stress, however, the bursa can become thickened, inflamed, and filled with excess fluid — a condition known as bursitis.

Chronic bursitis is the most common form and develops slowly as the result of repeated, low-level irritation. Acute traumatic bursitis is much less common and most often seen in athletes who repeatedly move their extremities against a hard surface or bend a particular joint too much. Along with the knee and elbow, the shoulder is among the most common sites for bursitis. Chronic bursitis causes swelling and, sometimes, pain and a feeling of warmth. Acute traumatic bursitis features a rapid onset of swelling, usually with some tenderness and warmth. If the bursa becomes infected, the swelling, pain, and feeling of warmth can become extreme.

Immobilization with a splint, icing, anti-inflammatory medications or injections, stopping the aggravating activity, and providing cushioning for the affected area are common treatments for bursitis. Acute traumatic bursitis may require aspiration, in which excess fluid and blood are drained from the bursa. Infected bursa must be treated with antibiotics. Surgery is rarely needed. Shoulder bursitis can happen on its own or in combination with many other shoulder problems, including impingement and rotator cuff tendonitis.

Osteoarthritis

elderly woman holding shoulder in pain

Osteoarthritis (OA) is the most prevalent form of arthritis. Of the 54.4 million Americans with arthritis, 32.5 million of them have osteoarthritis (via the Osteoarthritis Action Alliance). Although the majority of people with OA are older adults, 12% are under 45 and 57% are younger than 65.

OA is considered a form of degenerative or mechanical arthritis — a "wear and tear" condition (per the Mayo Clinic). Over time, the cartilage that cushions the ends of the bones in a joint wears away, causing bones to rub against one another, leading to pain, stiffness, reduced range of motion, and grinding noises. The breakdown of the joint can happen simply as a result of getting older or because of injuries or repeated stress on the joint. First-line treatments include over-the-counter or prescription pain relievers and physical therapy. Injections of corticosteroids or joint lubricants may also be helpful. In severe cases, joint replacement may be necessary.

The Arthritis Foundation noted that "shoulder OA is not as common as OA of the hip or knee, but it is estimated that nearly 1 in 3 people over the age of 60 have shoulder OA to some degree." Because the shoulder is actually two joints, where pain is felt indicates which joint has OA. OA in the glenohumeral joint causes a deep, aching pain in the back of the shoulder, while arthritis in the acromioclavicular joint produces pain at the top of the shoulder that may radiate up the side of the neck.

Bone spurs

doctor gesturing to shoulder x-ray

According to University of Michigan Health (UMH), "a bone spur (osteophyte) is a bony growth formed on normal bone." Contrary to what their name would suggest, bone spurs usually aren’t spikey — they’re most often smooth. As UMH explained, "a bone spur forms as the body tries to repair itself by building extra bone. It typically forms in response to pressure, rubbing, or stress that continues over a long period of time." Bone spurs aren’t innately painful, but the excess bone can rub on other bones, tendons, ligaments, or nerves, causing damage to these structures and pain.

Along with the hands, hips, knees, feet, and spine, the shoulders are one of the most common places for bone spurs to form. Once again, the shoulder joint’s amazing mobility is also a liability. Over time, as the tendons of the rotator cuff move through the narrow space between the bones of the shoulder, they can rub on the bones, prompting the formation of bone spurs. These bone spurs pinch the rotator cuff tendons, leading to irritation, inflammation, stiffness, weakness, and pain. In severe cases, the bone spurs may even tear the tendons. Shoulder bone spurs are common in older individuals and those who put their shoulders under frequent stress because of their occupation or hobbies.

If shoulder bone spurs are rubbing against other structures in the shoulder and causing pain, treatment options include ultrasound, deep tissue massage, anti-inflammatory drugs, and physical therapy. In some cases, bone spurs are surgically removed.

Brachial plexus injury

woman holding neck and top of shoulder

Sometimes, nerve damage is at the root of shoulder pain. The brachial plexus is a network of nerves that sends signals from your spinal cord to your shoulder and down to your arm and hand. If those nerves are injured, it can lead to shoulder pain and other neurological issues (via the Mayo Clinic).

Injury to the upper brachial plexus occurs when the shoulder is forced down as the neck stretches up, while the lower nerves are damaged when the arm is forced above the head. Minor brachial plexus injuries, known as stingers or burners, occur when the nerves are stretched or compressed. This produces an electric shock or burning sensation in the affected shoulder and arm, and may sometimes also cause weakness or numbness. These types of injuries are common in contact sports and usually only last a few seconds or minutes. More severe injuries involve tearing of the nerve fibers and are often the result of car accidents or other traumatic impacts. In addition to causing severe pain, these injuries may make it impossible to move the affected shoulder, arm, and hand. Brachial plexus injuries can also lead to chronic pain, stiff joints, and muscle atrophy.

Mild brachial plexus injuries will usually heal on their own without treatment, but more serious injuries may require pain medication, physical therapy, and surgery to reattach or replace damaged nerves. Because nerves grow very slowly, it can take years to fully recover from a severe brachial plexus injury.

Polymyalgia rheumatica

elderly woman holding both shoulders in pain

According to the Mayo Clinic, "polymyalgia rheumatica [PR] is an inflammatory disorder that causes muscle pain and stiffness, especially in the shoulders and hips." PR usually occurs on both sides of the body at once. Symptoms include achiness or pain in the shoulders that radiates into the neck or upper arm, stiffness in the affected shoulder and arm, and limited range of motion. Other less specific symptoms include fatigue, mild fever, malaise, and loss of appetite. Although experts aren’t sure what causes PR, they believe it’s a combination of genetics and environmental factors. PR also appears to be closely related to giant cell arthritis, another inflammatory disorder. PR is most often diagnosed in older individuals, and women are two to three times as likely as men to have the condition.

Doctors use a combination of physical exam, imaging, and blood tests to diagnose PR. Two commonly used blood tests are erythrocyte sedimentation rate (sed rate) and C-reactive protein, both of which are markers for inflammation in the body. PR is usually treated with a low dose of an oral corticosteroid such as prednisone. Treatment often lasts for at least a year. Being on corticosteroids for so long can have negative side effects, including reduction in bone density. To offset this, people with PR are usually advised to take calcium and vitamin D. Physical therapy may also be needed.

Heart attack

heart attack pain radiating out from man's chest

According to the Centers for Disease Control and Prevention (CDC), each year, approximately 805,000 Americans have a heart attack. That’s one heart attack every 40 seconds. Of these, roughly 605,000 are first-time heart attacks. Although heart disease is the leading cause of death in the United States, only about 12% of heart attacks are fatal, thanks to speedier care after a heart attack (via The Washington Post).

One important key to surviving a heart attack is recognizing the symptoms quickly and getting immediate medical attention. While chest pain is the quintessential heart attack symptom, this pain can often radiate to other parts of the body, including the shoulder. It also varies by gender. In men, pain can radiate to the left shoulder and down the left arm. Women may feel radiated pain in a variety of places, including the shoulder blades. Because this pain isn’t felt in the chest, many people write it off as indigestion or something else minor (via Honor Health).

Penn Medicine advises: "Call 911 if you have sudden pressure or crushing pain in your shoulder, especially if the pain runs from your chest to the left jaw, arm or neck, or occurs with shortness of breath, dizziness, or sweating."