Problems 2 Yrs After Shoulder Injury

I injured my shoulder approximately 2 years ago. Diagnosis was never confirmed, one physical therapist said I had a protracted shoulder girdle. . . After 2 physical therapists and a year of doing the rehab my shoulder no longer hurts and is slowly getting stronger.

My problem is that whenever I do shoulder/chest exercises. Particularly bench - with dumbbells or a barbell my right side (the uninjured side) gets much more of a pump, both in the shoulder and chest.

And the following day or so my right side will be much more sore than my left(injured) side. I have no idea why this is the case, and I don’t want to end up being called biggie smalls due to a large right pec and a smaller left one, not to mention there is already a slight difference in shoulder size.

Anyone know why this might be happening? And how I can work toward fixing it?
I’d be much obliged! Thanks for reading.