I had breast cancer surgery and radiation. A few years afterward, I started having really bad (affected side) shoulder pain. Long story short, it turned out to be a torn rotator cuff. It was extremely painful. I had heard other "thrivers" mention shoulder issues and polled some of them. My very informal polling leads me to believe that the risk for torn rotator cuff seems to be remarkably elevated in breast cancer survivors. Most of us have had surgery, radiation, and an array of drugs. Some of us have developed lymphedema. It is not surprising that perhaps our shoulders have been impacted. (I would love to see a study!) At any rate, once I convinced my doctors to take my complaints seriously, I had an MRI and, later, managed to get a steroid injection. The injection has remarkably improved my shoulder pain and quality of life. My impression is that some doctors and health insurance plans follow up with physical therapy. My plan has refused to pay for it. I hope you have luck addressing your shoulder pain!