What Causes Hot Flushes And Joint Pain?

I had a mastectomy with lymph nodes removed - 4 of which were cancerous, exactly 4 years ago (right side) - Grade II diagnosis. Underwent chemotherapy followed by 5 weeks radiotherapy (Dec 2010). Started on tamoxifen the following January. In Nov 2013 I had two seperate blood clot incidents in my right arm and was changed to Letrizole. After about 4 weeks the hot flushes returned, more aware of the neuropathy in feet and by end of January joint and bone pain that was debilitating. One week ago I was changed to Aromasin in the hope that the aches etc will go. I am swimming regularly and eat well. Flushes are becoming a litle less persistent but the joint pain and stiffness still present although I think (maybe hope) it is getting slightly less angry. Could you give your views please and the side effects associated with my third option. Thank you - Jac