Not really sure what exactly is happening. Are you getting a sliding, “clunk” feeling when you row your arm back? Is the area you’re pointing at hurt when you try to stand with correct postrue (shoulders pulled back)?
Those are both happening to me, actually my right shoulder has those and will completely lock up if I do rear delt exercises with a pronated grip. My issues started after being in a full arm cast for about 2 months, my PT noticed my serratus anterior was ridiculously weak so im doing some stuff for that (incline scap push ups, DB pushaways) and working on external rotation.
Can’t say they’ve helped this issue, but from what my PT has noticed my winging of my scapula has improved. For the record, I always sleep on my right side or my back so that could contribute. Now I sleep on my left side or back.