It's not a question of whether or not you know how to do them. A quality PT should be assessing the intrinsic mobility of the joint, the position of the joint, and taking the joint through passive ROM under their manipulation to gauge restriction and movement capacity, then watching you do prescribed exercises to ensure not just that you're doing them correctly but that your shoulder is exhibiting a fundamentally sound movement pattern that is constructive and not destructive.
Honestly, after a shoulder surgery, I think it's extremely irresponsible for a physician to have a patient begin rehab exercises without first having them evaluated by a physical therapist, and then having them do the exercises initially under direct supervision and evaluation.
the answer to your question is impossible for any of us to answer because we don't know WHY you are having the pain you are having. Is it because you are experiencing normal post operative pain? Perhaps. Is it because the shoulder is not moving functionally and you are overstressing the repaired areas? Perhaps. Is it because you are doing an exercise your shoulder is not genuinely prepared to do at this time? Perhaps.
Only one way to make that determination, and that's to utilize a physical therapist to evaluate and advise you.
Volkl Organix V1 Pro
Pacific Gut 17 gauge mains at 54lbs/MSV Co-Focus 17L gauge crosses at 50lbs