New pain one year after diep flat reconstruction (two years post mastectomy and radiation).

For the past 6-8 weeks I've been experiencing increasing pain under/next to reconstructed breast. It is radiating around my shoulder area and can be painful when breathing. Very sensitive to touch, but the pain seems to come and go, usually worse towards end of day and night and can wake me up when its at its worst. Can this pain be caused due to scar tissue? I had a non eventful recovery post surgery with no real pain and no problems