A shoulder that’s started hurting and won’t lift the way it used to is one of the most common things that walks through the door. The problem is that “shoulder pain and stiffness” describes at least four completely different conditions — and the treatment that helps one can actively make another worse.
People arrive fairly sure they have frozen shoulder because they googled the symptoms. Sometimes they’re right. Often they’re not — and the difference matters more here than for almost any other joint, because the direction of treatment for a frozen shoulder is in some ways the opposite of what a rotator cuff tear needs.
The four that get confused
Almost every “stiff painful shoulder” that isn’t from an acute fall is one of these:
- Frozen shoulder (adhesive capsulitis) — the joint capsule inflames and contracts, mechanically tightening the joint. Loss of motion in every direction is the hallmark.
- Rotator cuff tear — a tendon (usually supraspinatus) is torn or worn. The shoulder hurts with certain movements and may lose strength, but it’s not uniformly stiff.
- Subacromial impingement / bursitis — structures get pinched under the shoulder blade when you lift your arm overhead. Pain sits in a specific arc, not all the time.
- Shoulder (glenohumeral) osteoarthritis — the joint surfaces wear. Deep ache, crepitus (grinding), and stiffness, most common in older patients or after past injury.
They feel similar from the inside. The way you tell them apart is mostly by how the shoulder moves — not by how it feels.
The single most important test: passive movement
If you remember one thing from this article, make it this. The defining difference between a capsular problem (frozen shoulder, osteoarthritis) and a muscle/tendon problem (rotator cuff tear, impingement) is what happens when someone else moves your arm for you.
In a frozen shoulder, the capsule is tight and contracted. So whether you lift the arm yourself (active movement) or a physio lifts it for you (passive movement), it hits the same hard stop. Active and passive range are limited equally. The block is structural — the capsule physically won’t let the joint go further.
In a rotator cuff tear, the muscles and tendons that drive the movement are the problem, not the joint itself. You can’t lift your arm fully on your own — but when someone else lifts it for you, it goes much further. The joint has the range; the muscles just can’t produce it. Active range is less than passive range.
This is why a physio will always test both, in several directions, early in the assessment. It’s the single most decisive piece of information in a shoulder exam.
The telling features of each
Alongside movement testing, a few clinical signals point toward one diagnosis over another:
- Frozen shoulder— typically 40–60 years old; strong links to diabetes and thyroid conditions; no clear injury; external rotation (turning the arm outward) is lost first and most; pain is often worse at night and can disturb sleep.
- Rotator cuff tear — more likely over 50 or with repetitive overhead work; there may be a specific moment you felt it; weakness lifting the arm out to the side, especially against resistance; pain down the outer arm.
- Impingement / bursitis— a “painful arc” between roughly 60–120 degrees as you raise the arm; pinching or catching overhead; often tender to lie on.
- Osteoarthritis — older age or a history of trauma; grinding or clicking you can feel; deep ache that worsens with use and eases with rest; stiffness that loosens as you warm up.
None of these on its own is conclusive. It’s the pattern — age, onset, movement findings, and a handful of specific tests taken together — that pins it down.
When imaging comes in
A common assumption is that you need a scan to know what’s going on. In practice, the diagnosis is usually clear from the assessment before any imaging. Frozen shoulder in particular is a clinical diagnosis — the movement pattern tells the story, and an X-ray is mostly useful to rule osteoarthritis out, not to see frozen shoulder in.
Imaging earns its place when something doesn’t fit — a suspected cuff tear that needs confirming, a traumatic injury where a fracture has to be excluded, or a presentation that isn’t responding as expected. The trap is scanning first and assuming the picture explains the pain: plenty of pain-free shoulders show tears and wear on ultrasound. A scan without an assessment can mislead more than it reveals.
Why the label matters so much
The reason this matters isn’t academic. The conditions pull treatment in genuinely different directions:
- Frozen shoulder in its painful early phase needs to be left largely alone— gentle movement within limits, pain control, and patience. Aggressive stretching makes it worse. The phases and what’s appropriate at each one are covered in detail in the full frozen shoulder guide. Read the full treatment breakdown →
- A rotator cuff tear usually needs progressive strengthening of the cuff and shoulder blade muscles to offload the torn tendon and restore control. More on rotator cuff tears →
- Impingementresponds to sorting out the mechanics of how the shoulder blade moves — posture, control, and the muscles that keep the joint centred. More on shoulder pain when lifting →
So a shoulder that’s stiffening up could be frozen shoulder — or it could be something that needs a completely different approach. The good news is that telling them apart is something a thorough assessment does well, and it’s the difference between treatment that actually moves you forward and treatment that sets you back.