dmcook I was on Tamoxifen for 4yrs, I know there are side effects, maybe I suffered them and was just used to it, I really don't know. I always had slight pain through my body anyway due to Fibromyalgia but the Tamoxifen didnt add to it. The other thing was too I was 43 when I went on it and was pre menopausal, I dont know if that had something to do with it as in I didnt notice alot. Though at recurrence at 47 Chemo threw me into menopause which brought on enormous pain due to both of those things and Arimidex well, is renowned for joint pain, so all those things together. But I honestly believe if I wasnt thrown into menopause my symptoms may not have been as harsh. Magnesium in powder form, I take once a day, with Vit D and C. I suffer severe cramping in my back upper and lower everywhere and in my chest, the chest is due to radiotherapy 2011 and only thing finally helping with back cramping is my exercise physiologist we do a mountain of stretch type exercises, as chemo shrinks the sheath over the muscles. So everything really is manageable, just have to find the ways to manage it. Hugs Melinda xo