I tore My right Shoulder a few times. Never even thought of going to a Doctor.
Rehab was 3 yrs of light shoulder Extensions, 2-3 times a week with 20 lbs..
Finally back to overhead pressing and 50lb extensions again!
Point is, find a exercise that does not hurt and let time and blood flow heal it!
Treading Water worked well also...
The weird thing is no exercises really hurt. Whenever it happened I wasn't able to finish the rep but since there was no pain I went back and redid my whole set and hit military dumbbell press afterwards.
I think if it was a tear I'd have known right there on the spot. But for it to randomly give out like that seems like something funny is going on.