Pain: Has anyone else experienced this?

I finished my month of radiation after DCIS breast cancer in my right breast. All went very well. I'm an 81 year old extremely active (I walk 8 miles a day) woman. A couple of weeks after the radiation ended, I developed severe pain in my right shoulder, followed by pain in my right groin area, then my left shoulder and left groin, though not as bad on that side. The PT has no idea what it could be. I was not in an accident, didn't take a fall, didn't do any type of exercise that I don't normally do. Someone I was talking to mentioned radiation caused fibrosis. Does anyone have any experience with this? I'm awaiting a call back from my radiation oncologist. Meanwhile, the only way I can get through the day is with Gabapentin and Ibuprofin 800. Help!