I can tell you that 5 years after surgery, I still feel a little soreness at the lumpectomy incision (nerves regenerating, I was told), and sometimes a real pain under my arm where the nodes were removed. My scar area from the lumpectomy is still hard from scar tissue. The pain certainly isn't constant, but I remember being told that some pain will last quite a long time. Not enough for meds, just annoying.
Regarding the burn. 5 weeks is a long time for a radiation burn to not have healed. I'd check into this. I'm sure there is something your Rad Onc can recommend.
After treatment can be really hard! I was used to someone seeing me all the time, then I was all on my own! Please don't hesitate for one second to call any doctor treating you. They want you to. I promise.