The rotator cuff is four small muscles wrapping the head of the arm bone; the one that sickens first sits under a bony shelf on top. It isn't being pinched and chewed up by that shelf. It's degenerating from the inside, like a frayed rope giving way under everyday loads. The pinch happens, but it isn't what drives the pain, which is why shaving that bone doesn't help ¹.

The surgery doesn't beat a fake. Decompression, keyhole surgery to shave that bony shelf, was for decades one of the world's most-performed operations. Against a sham where the surgeon opens the joint and shaves nothing, it's no better on pain or function ^{1 2}. A Cochrane review of 1,062 patients calls that high-certainty, with a small risk of harm on top ³; a guideline panel now recommends against it ⁴.

The scan lies. Send a pain-free shoulder for an MRI and a third show a tear; over 60 it's more than half ^{5 6}. A village mass-screening found two-thirds of its tears in people with no pain ⁷. So a tear on your sore shoulder may predate the pain by decades, and treating it isn't treating the pain.

Loading works. Long-standing cases given slow, heavy cuff-and-scapula exercise did far better at three months than those given generic exercises; one in five still chose surgery, against nearly two in three of the generic group ⁸. It's first-line management now ⁹.

Load the tendon; don't rest it. Daily, for roughly twelve weeks.

The whole thing is an eight-to-twelve-session course and an elastic band: near-free in public systems, a few hundred to a thousand dollars privately. The paths you're told to skip cost far more.

Sleep returns first, usually within two or three weeks, before the movement pain has cleared: you roll onto that side and fall back asleep. By the second month the seatbelt grab stops registering. By three months most people are functionally back, with trial function scores up about 25 points on a 100-point scale ⁸. The tendon ends up stronger than before the episode.