Dear memelori: Unfortunately, this type of problem sometimes happens to people who have had radiation therapy. It is not common, but occasionally happens. It is unlikely, 12 years later that it is scar tissue from the surgery. Nonetheless, the fact that you have had lymph nodes removed and then radiation to the remaining nodes is probably the cause of the lymphedema. It would be a good idea to seek help at a lymphedema clinic or, if that is unavailable, occupational therapists generally have experience dealing with these problems and may be able to offer some practical assistance to dealing with both problems. It is reasonable to have the MRI just to be sure there is no new problem.