Here are some that won't mess up your normal routines and will do wonders, injury or not. This is rehab stuff assuming we take it easy. Once there is improvement you can add something resistance wise , like cuban press.
You can youtube search these ones, to make it easy.
Total shoulder girdle health . Do these 3 times a week. Can do them at home in some cases.
1) Serratus Anterior (Activation movements) are in here for you which should help. This sucker stabilses the scapular movement,
a) Scapular pushups. Just a pushup with you extending and retracting the shoulder blades. The movement is shallow( no where near the ground , motion is small) .The arms straight. Do 3 sets of 20-25
b) Single dumbel scapular protraction. Lay on a bench. Fairly light weight dumbell in one hand straight up. Straight arm. As above move the dumbel up and down with the scapular motion. 20-25 reps as above.
c) Scapular wall slides.
d) Prone Cobras held for time.
e) External rotator bands
f) Shoulder dislocates with band or a stick ( can use a barbell if you are strong).
Try these ones for a month.