I still have pain after 5 years! My surgeon told me I'd have pain the rest of my life to some degree. Nerves regenerating, etc. Sometimes I get a dull pain, sometimes it's a sharp pain. It used to scare me, but now I'm used to it.
Most of my pain comes from the area where my nodes were removed. Lots of nerves cut there.
Any time I need reassurance, I go to my Oncologist and she pokes around to make sure I'm OK! I don't go to my surgeon any longer. You may want a follow up with your Rad Onc to see if he/she feels the pain is related to radiation.