You will need to try to diagnose the cause of the pain before you can cure it. A good PT technician can help with this by figuring out which muscles or ligaments are involved and whether specific exercises trigger more pain or will help. If it's just constant pain whether or not you are using the arm, then I would go back to the surgeon, or get a referral for a 2nd opinion from your primary care doctor, if the surgeon does not take you seriously.

Let me just say, I went through extensive PT back in 2020, right in the shut down, during pain management treatment. The therapist released some frozen muscles and vertebrae over a period of several months, taught me some stretches & exercise and coping mechanisms, and I was good to go. Fast forward to this Summer, after an exacerbation of my lung issues & a "mystery" problem with my neck - my doc sent me back for a "tune-up" - today I was discharged from therapy even better than before. He helped me increase the range of motion in my neck and spine from 50% (for my age & issues) to over 90%. He designed some new stretches and exercises to address my ongoing back issues. I will do a check-in with him in December.

I second @ddsack in the suggestion to get PT - but ask for a "full assessment & rehab plan" not just some set exercises as usually prescribed post-surgery.

Sue