I had radiation in 2012 it actualy agrivated my cording in my arm, don't forget it tightens everything up so don't forget back to the exercises l had extremely sore and hard breasts up to 5 months ago the breast would go up and down especially if I over do it. The radiologist said it can take years to settle. I also had a very sore muscle in the front of the chest which was eased with voltaren gel as suggested by the onco. It's only the last 2 months it's softening and not so hard, try massaging the breast in the shower with sorbelene to get the blood flowing. Regards adean