Good info. I tore my left rotator cuff. I found that doorway stretches, removing behind the neck press and keeping good form on lifts to help.
I also use a very light weight, 3 pounds, and lie down on my side with my elbows pinned to the side and the arm bent at a 90 degree, then do 15 reps of internals and external rotations for each shoulder. You don't wanna build it up, but it will make it more stable and the endurance will improve. Definitely warm up well.