Shoulder bursitis is inflammation of a small, fluid-filled sac called the subacromial bursa that sits between the bones and tendons at the top of your shoulder. This bursa normally acts as a cushion, preventing the rotator cuff from grinding against the bony roof of your shoulder every time you raise your arm. When it becomes irritated and swollen, the space it occupies gets crowded, and movements that were once painless start to hurt.
Where the Bursa Sits and What It Does
The subacromial bursa is tucked into a narrow gap called the subacromial space. Above it sits the acromion (the bony point at the top of your shoulder), the coracoacromial ligament, and the deltoid muscle. Below it lies the supraspinatus, one of the four rotator cuff muscles responsible for lifting your arm. The bursa’s job is to protect that muscle from being worn down by the bone above it every time you move your arm overhead, out to the side, or behind your back. When the bursa swells, there’s less room for everything to glide smoothly, and the resulting friction and pressure produce pain.
What Shoulder Bursitis Feels Like
The hallmark symptom is pain at the outer or front of your shoulder. It can arrive suddenly after a day of heavy overhead work, or it can build gradually over weeks until you notice it’s always there as a dull, persistent ache. The pain typically sharpens into a pinching sensation when you lift your arm above your head. Reaching behind your back, pulling on a seatbelt, or throwing a ball can all trigger it.
Nighttime is often the worst. Lying on the affected shoulder compresses the already swollen bursa, and many people find the pain wakes them up or keeps them from falling asleep in the first place. If the pain is limiting your daily activities or disrupting your sleep consistently, that’s a sign it needs attention rather than just time.
Common Causes
Repetitive overhead motion is the most frequent trigger. Painters, carpenters, swimmers, tennis players, and anyone who regularly reaches above shoulder height can develop bursitis simply from cumulative wear. Each overhead movement nudges the rotator cuff against the acromion, and the bursa absorbs that friction. Do it enough times, and the bursa responds by becoming inflamed.
A single injury or trauma to the shoulder, like a fall or a direct blow, can also inflame the bursa. Beyond mechanical causes, certain systemic conditions raise your risk. Rheumatoid arthritis and gout both promote joint inflammation that can spread to the bursa. Diabetes is another recognized risk factor. In rare cases, the bursa itself can become infected, a condition called septic bursitis, which typically causes redness, warmth, and sometimes fever alongside the pain.
How It’s Diagnosed
Diagnosis usually starts with a physical exam. Two common in-office tests help a provider assess whether the subacromial space is the source of your pain. In the Hawkins test, your arm is raised to 90 degrees in front of you with the elbow bent, then the provider rotates your shoulder inward. If this reproduces your pain, it suggests impingement of the bursa or rotator cuff. In the Neer test, the provider lifts your arm forward and overhead while holding your shoulder blade down. Pain during this motion points to subacromial irritation.
These tests are better at ruling out subacromial problems than definitively confirming them, so providers sometimes combine them with imaging. An X-ray can reveal bone spurs or changes to the acromion that narrow the subacromial space. An MRI or ultrasound can show whether the bursa is swollen and whether the rotator cuff tendons are intact. In some cases, a provider will inject a local anesthetic into the subacromial space: if the pain temporarily disappears, the bursa is almost certainly the source.
First Steps in Treatment
Most shoulder bursitis improves within a few days to a few weeks with straightforward, nonsurgical care. The initial approach combines rest, ice, and anti-inflammatory medication. “Rest” doesn’t mean immobilizing your shoulder entirely, which can lead to stiffness. It means avoiding the specific movements that provoke pain, particularly overhead reaching and heavy lifting, while continuing gentle, pain-free motion.
Icing the shoulder for 15 to 20 minutes several times a day helps control swelling, especially in the first few days. Over-the-counter anti-inflammatory medications reduce both pain and inflammation in the bursa. Together, these measures give the bursa time to calm down.
Physical Therapy and Rehabilitation
Once the acute pain begins to settle, targeted exercise becomes the most important part of recovery. The goal is to strengthen the muscles that support and stabilize the shoulder joint so the bursa is less vulnerable to repeated irritation. The key muscle groups include the rotator cuff (supraspinatus, infraspinatus, subscapularis, and teres minor), the deltoids, and the upper back muscles like the trapezius and rhomboids. Weakness in any of these can alter your shoulder mechanics and put extra stress on the bursa.
A typical rehabilitation program recommended by the American Academy of Orthopaedic Surgeons starts with stretching and progresses to strengthening, with stretches repeated at both the beginning and end of each session. Several stretches are particularly useful:
- Crossover arm stretch: Gently pull one arm across your chest at shoulder height, holding for 30 seconds. This targets the back of the shoulder. Four repetitions per side, five to six days a week.
- Passive internal rotation: Using a light stick held behind your back, pull horizontally to stretch the top of the rotator cuff. Hold for 30 seconds, four reps per side.
- Passive external rotation: With the stick in front and your elbow pinned to your side, push outward to stretch the back of the rotator cuff. Same hold time and repetitions.
- Sleeper stretch: Lie on your affected side with your arm bent at 90 degrees, then use your other hand to gently press the forearm toward the floor. This stretch targets the muscles that rotate the shoulder outward. Four reps, three times a day.
The key principle across all of these is stretching to the point of a gentle pull, never into sharp pain. Strengthening exercises are layered in as tolerance improves, often starting with resistance bands before progressing to light weights.
Corticosteroid Injections
When rest and physical therapy aren’t enough, a corticosteroid injection into the subacromial space can provide significant relief. In one study of post-surgical shoulder patients receiving these injections, nearly 95 percent reported at least mild to moderate improvement in pain and function within four to six weeks. By eight to twelve weeks, the benefits had started to diminish for some patients, which is why injections are typically paired with physical therapy rather than used alone. The idea is to create a window of reduced pain that lets you do the exercises needed for lasting improvement.
The injections carry a low risk profile. In the same study, no infections, tendon ruptures, wound healing problems, or worsening of symptoms were reported. Most providers limit the number of injections to a few per year to avoid potential long-term effects on surrounding tissue.
When Surgery Becomes an Option
Surgery is reserved for cases that don’t respond to at least six months of nonsurgical treatment. The most common procedure is subacromial decompression, an arthroscopic surgery where a surgeon shaves away a small amount of bone from the underside of the acromion to create more room for the bursa and rotator cuff. The inflamed bursa may also be removed during the same procedure.
Outcomes for this surgery are consistently positive when patients are carefully selected. Candidates who respond best tend to meet a specific profile: pain with overhead activity, a positive Hawkins test, at least temporary relief from a prior steroid injection, and imaging evidence of bone changes at the acromion. In patients meeting all four criteria, outcomes are significantly better. Long-term studies with ten or more years of follow-up show lasting functional improvement, and one landmark study found excellent or good results in nearly 90 percent of patients regardless of whether they also had minor rotator cuff damage. Recovery typically brings meaningful improvement in function and quality of life by about 15 months after the procedure.
For perspective, in one controlled trial comparing surgery, structured exercise, and placebo treatment over 30 months, 68 percent of surgical patients improved compared to 61 percent in the exercise group and 25 percent in the placebo group. Notably, half of the exercise group and 22 percent of the placebo group eventually chose to undergo surgery, suggesting that while exercise works for many people, a significant portion still need the surgical option.