I have breast cancer (had chemo, surgery and radiation) on my left side and am currently having one chemo drug for a year (Her 2 gene). In the last two months I have noticed that my left clavicle bone below my neck is bigger and feels very different. No pain, but concerning. I see my oncologist next week, but she has said in the past that the radiation might have caused inflammation, but I am still concerned. She also said that most people have one collar bone bigger than the other, and I am left handed, but the end of it feels really different.