I also experienced the same thing you are describing. Throbbing in my lower back with each heart beat. I told my Dr. but she didn't seem concerned. I have switched Dr.'s since then. Not for that reason....many. I was diagnosed in late Jan./early Feb. 2013. I just turned 60 in Jan. and was hoping this yr. would be better. Last yr. around the same time (Feb.2012) I lost my youngest son who was only 26 yrs. old...suddenly. My first Dr. told me to pull myself together that half the fight is your emotional state. (Such a kind thing to tell a mother who is still grieving) . My breast cancer is Stage 2, Grade 3 which is aggressive. It had spread to the lymph nodes. Have had only 1 round of chemo and sch'd. for the 2nd round next Monday. Am taking Taxotere, Cytoxen, and Adriamycin. I had every side effect they warn you about except vomiting. I really am glad I found this site.