I don't really know about odema in the breast Laura but I do know that lymphodema in the arm can develop at any time down the track after lymph node removal. My Mum developed lymphoedema 10 years - yes 10 years! - after having breast cancer and just four lymph nodes removed (possibly more destroyed by radiation therapy). She had been run down and suffered a bout of shingles which seemed to bring it on. I would go and get the swelling checked out asap. Apparently the sooner it is treated the less severe it is (with arms anyway). Good luck.