Shoulder tendonitis is inflammation of the tendons in your rotator cuff, the group of four tendons that hold your shoulder joint in place and allow you to lift and rotate your arm. It typically develops from repetitive overhead movements or age-related wear and tear, and it ranges from mild stiffness to pain severe enough to disrupt sleep and daily tasks.
Which Tendons Are Involved
Your rotator cuff is made up of four tendons: the supraspinatus, infraspinatus, teres minor, and subscapularis. Together they wrap around the ball of your shoulder joint and keep it centered in its socket. The supraspinatus, which runs along the top of the shoulder, is the one most frequently affected because it sits in a narrow space beneath a bony ridge called the acromion. Every time you raise your arm, this tendon can get pinched between the bone above and the joint below.
Two things drive the damage. First, the tendon gets physically compressed against surrounding bone during repetitive overhead movements. Second, the tendon itself gradually degenerates with age as blood supply decreases, weakening the tissue and making it less able to handle stress. In most people, it’s a combination of both: the tendon weakens internally, the shoulder mechanics shift slightly, and compression from surrounding structures accelerates the breakdown. Over time, this cycle produces ongoing inflammation, progressive tissue damage, and eventually partial or complete tears if left unaddressed.
Common Causes and Risk Factors
The strongest risk factor is repetitive or overhead arm movement. Occupations like carpentry and painting put significant strain on the rotator cuff, as do sports like tennis, baseball, and swimming. Any activity that requires you to repeatedly lift your arm above shoulder height creates the kind of repetitive loading that triggers tendon inflammation.
Age plays a major role as well. Blood flow to the rotator cuff tendons naturally decreases as you get older, which slows healing and makes the tissue more vulnerable to small injuries that accumulate. This is why shoulder tendonitis becomes increasingly common after age 40 even in people who don’t do heavy overhead work. Poor posture, weak shoulder blade muscles, and previous shoulder injuries also increase risk by changing how forces distribute across the joint.
What Shoulder Tendonitis Feels Like
The hallmark symptom is pain at the tip of the shoulder that can radiate down the upper arm. You’ll typically notice it most when lifting your arm overhead or twisting it, like reaching for something on a high shelf or fastening a seatbelt. Many people also report a dull, persistent ache even at rest.
Other common signs include:
- Night pain that worsens when lying on the affected shoulder
- Stiffness and difficulty holding your arm in certain positions
- Mild swelling or tenderness at the front or top of the shoulder
- A clicking sound when moving the shoulder through its range
- Loss of mobility, particularly with overhead reaching
If tendonitis progresses without treatment, complications can develop. Calcium deposits sometimes build up within the inflamed tendons, a condition called calcific tendonitis, which further restricts motion. In more severe cases, the weakened tendon can partially or completely tear, leading to significant weakness and loss of function.
Tendonitis vs. Tendinosis
These terms sound nearly identical but describe different stages of tendon damage, and the distinction matters because treatment timelines differ significantly. Tendonitis refers to acute inflammation from sudden overloading of the tendon. It involves actual inflammatory cells at the injury site and typically heals within several days to six weeks with appropriate rest and treatment.
Tendinosis, by contrast, is a chronic degenerative condition. When a tendon is repeatedly stressed without adequate recovery time, its internal structure breaks down. The organized collagen fibers that give healthy tendons their strength become disorganized and replaced by weaker, immature tissue. Under a microscope, the tendon shifts from a white, firm, glistening surface to a dull, brownish, soft one. Inflammatory cells are rarely present in tendinosis, which is why anti-inflammatory treatments alone often don’t resolve chronic shoulder pain.
Early-stage tendinosis caught promptly can improve in 6 to 10 weeks, but chronic tendinosis may take 3 to 6 months to heal. In some cases, effective treatment takes up to 9 months. Many people diagnosed with “tendonitis” actually have tendinosis, which is why recovery sometimes takes longer than expected.
How It’s Diagnosed
Diagnosis starts with a physical exam. Two tests are particularly useful. In the Neer test, a clinician stabilizes your shoulder blade with one hand while passively raising your internally rotated arm. Pain during this movement suggests the tendon is being compressed. This test catches about 72% of cases. The Hawkins-Kennedy test is slightly more sensitive at 80%: your arm is held at 90 degrees with your elbow bent, then quickly rotated inward. Pain in the top of the shoulder during this motion is a positive result.
If the clinical picture is unclear, or if a tear is suspected, imaging may follow. Ultrasound can visualize tendon thickening and tears in real time, while MRI provides a detailed look at the full extent of tendon damage and surrounding structures.
Treatment Without Surgery
Conservative treatment is the first-line approach, and for most people it works. A large network analysis comparing different treatment strategies found that exercise therapy targeting the rotator cuff and shoulder blade muscles produced significant pain relief compared to standard medical care, and that relief held up at one year of follow-up. Exercises focusing on both the rotator cuff and the muscles that stabilize the shoulder blade were particularly effective.
Interestingly, adding other therapies on top of targeted exercise provided questionable additional benefit. The exercise itself was the primary driver of improvement. A typical rehabilitation program involves gradual strengthening of the rotator cuff and shoulder blade stabilizers, starting with low-resistance movements and progressing as pain allows. Consistency matters more than intensity, and most programs run 6 to 12 weeks before meaningful progress is evident.
Corticosteroid injections can help manage pain during the early stages of rehabilitation, particularly if inflammation is severe enough to prevent you from doing exercises. Current guidelines suggest spacing injections at least 2 to 3 weeks apart, up to 3 months between doses, and stopping when pain relief plateaus. Injections are a tool for enabling recovery, not a standalone fix.
Rest from aggravating activities, ice, and over-the-counter anti-inflammatory medications round out the conservative approach. Complete immobilization is generally not helpful and can lead to stiffness, so the goal is modified activity rather than total rest.
When Surgery Becomes an Option
Surgery is typically considered only after conservative treatment has been given a fair trial and failed. Clinical guidelines use six weeks as a key benchmark: if you haven’t achieved meaningful improvement (roughly 30 to 50% functional gains) within 4 to 6 weeks of consistent conservative treatment, a specialist referral is reasonable.
For partial-thickness rotator cuff tears involving more than half the tendon’s thickness, surgery may be considered after at least six weeks of conservative care. For tears involving less than half the tendon, another six weeks of conservative treatment is recommended before revisiting the surgical question. Full-thickness tears that haven’t responded to six weeks of rehab and are deemed repairable are also candidates for surgery.
For calcific tendonitis that doesn’t resolve with conservative management, surgical removal of the calcium deposits is generally considered after 12 weeks. Most shoulder surgeries today are performed arthroscopically through small incisions, which shortens recovery compared to open procedures.
What to Expect During Recovery
Mild shoulder tendonitis caught early often improves within a few weeks of rest and targeted exercise. Moderate cases typically require 6 to 12 weeks of consistent rehabilitation. If the condition has progressed to tendinosis, with structural changes in the tendon itself, recovery stretches to 3 to 6 months or longer.
Post-surgical recovery varies by procedure, but most people are in a sling for several weeks, begin gentle range-of-motion exercises within the first few weeks, and gradually return to full activity over 3 to 6 months. The most important factor at any stage is not pushing through significant pain during rehabilitation. Tendons heal slowly because of their limited blood supply, and re-aggravating them resets the clock.