Don’t know where to start

I had Bariatric surgery on 6-13-2022. When I woke up my shoulder was in pain. They said that gas had went into my shoulder. When I got home it continues to hurt. It felt impacted. They still said it was gas. But it continued to bother me. So I called the Dr office and his nurse said they probably did something during surgery when they positioned me. And scheduled and MRI. It say I had a small rotator cuff tear. Then she scheduled me to see an orthopedic surgeon and he wants me to do therapy. I called the dr office because the therapy place stated that I had to pay for my own therapy. The dr office acted like they were handling it. But then they stated that it doesn’t have anything to do with them. It’s the hospitals fault and I need to file a claim with the hospital.