What Could Achy Pain In Breast Post Lumpectomy And Radiation Indicate?

Hi, I had early stage breast cancer twice and a lumpectomy in each breast...and radiation. Lately, I've noticed some achey pain in my breasts..NO LUMPS...and it's not every day..just occasional. I was wondering what it could be...it's kind of like the aches I had when I was younger and getting ready for my menses. THANKS, N YYYY@YYYY