I had single mastectomy in 2016 and have sore patches on ribs, both sides (have done for the last year or so). Had 6 sessions of chemo after surgery (adjuvant therapy) but no radio. Have had x-ray and apparently all good. If you're worried or concerned see your GP or oncologist (if you're still under one). Any pain or ache is a concern after what we've been through. I was told to report everything - even if it turns out to be nothing - best to be sure!