it reminds me of when my rotator got fucked.. it just went weak... honestly, the first thing i had to do was stay outta the gym for almost 14 weeks (but i was in pain)... then i started doing exercises that didn't cause major fatigue or serious ache during the work out.. .it sucks.. i can't do military press at all right now... after the injury i also had to drop my fly's down so far it was embarassing... but ...
basically i tried to take away SOME of the isolation during my exercises to slowly strengthen the cuff that WAS injured so all the strain wasn't on one spot..
one thing that is very simple that i started doing was taking a light plate... i had to start with 10's.. but at 45's now w/ no problem... hold them straight out and do raises as high as i could with control... up and down.. could only do like 4 reps in the beginning, but now i do 45's for 15-20 reps a set...
also... you see some older people doing them, but for the rotator.. it's a great rehab exercise... get on the smith machine... and if it has adjustable cable pully's (meaning they slide up and down etc), ... make it parallel to your elbow... bend your elbow 90 degrees.. and do slow rotations... if you don't have adjustable pully's... started with 5's/10's or 25's... and do the same exercise with a single plate... then to depending on where your injury is... do dumbell lateral raises... in front, and when i do them to the side, i can't do them with my arm fully extended i have to bend my arm at the elbow to decrease some of the gravity/strain on certain areas of my shoulder... and do side raises that way.... and of course, i noticed it was a 'little' challenging to do my real delts... but as i got that strengthened the center of my shoulder/rotator was slowly getting stronger b/c the other areas of the cuff were keeping the strain down.
If you are doing gear, then add something to retain a little water, or change your diet a little... after i was retaining a little water it was easier to do the movements untill i got stronger... then if you need to dry out a little, watch how it feels and see if the ache comes back...
it's not a rocket science move... but other than military press (and i can't do reverse arnolds either), my shoulders feel about 85%... if i had full range of motion w/o fatigue or pain i'd be doing military presses.. but i haven't had too yet... b/c i don't want to hurt myself before my chest/back/arms get stronger
i would love to hear other REAL rehab exercises though... as my shoulder still needs recovery.