It's not very likely to represent an effect of radiation at this late stage; likewise, problems with lymph drainage nearly always would present with swelling, especially of the arm. I think it's important to rule out recurrant or metastatic cancer, which might begin with mammogram and chest xray with rib views; possibly a bone scan. If those are ok -- and I'd guess they would be -- then I'd be thinking in terms of an unrelated musculoskeletal problem, such as pinched nerve, muscle strain, etc.
A related discussion,
Breast Cancer was started.
I TO HAVE HAD BREAST CANCER IT SOUNDS LIKE THE SAME SURGERY I HAD I WAS 37 YEARS OLD AT THE TIME AND I HAD ALL THE SAME TREATMENTS AND I HAVE ALOT OF PAIN IN MY SHOULDER AND ARM I HAVE HAD X-RAYS AND BONE SCANS AND KNOW ONE KNOWS WHAT THE PROBLEM IS AND MY PAIN COMES AND GOES IN THE SAME WAY MY DOCTOR GAVE ME CELEBREX TO TAKE AND IT DOES EASE THE PAIN FOR A LITTLE WHILE
Dear JMZ: This pain could be from a variety of things, including, possibly, late effects of radiation, although it's coming and going is a bit inconsistent with this. Additionally, it does not sound much like lymph node drainage. However, your pain is real and needs to be treated. Perhaps your GP could order an x-ray. Also, if he is unable to find the source, perhaps he can assist you in obtaining an appointment with a specialist. Also, is there any possibility that you can get health insurance? This would certainly help cover the cost of a proper work up.