Relaxed hang
Hang from a bar with straight arms and let the shoulders go up.
3 × 10–30 s
tendon
Flat tendons at the front of the upper arm bone, just below the shoulder, where the latissimus and teres major attach.
Carry the pull of the two biggest arm-pulling muscles to the arm.
Take the full load at the bottom of a hang, where the muscles are longest.
Hang from a bar with straight arms and let the shoulders go up.
3 × 10–30 s
Start at the top of a pull-up and lower yourself as slowly as you can to straight arms.
3 × 3–5
Other structures the same drills work.
General anatomy, simplified. It describes a structure, not anybody's shoulder, and cannot say what is wrong with yours.