I ve been having pretty severe migraine headaches, left side only, for the past three/four years. Seemed to have started about two years afterleft side LCIS and DCIS breast cancer and bilateral mastectomy. As migraine intensified they came with pain in the left side of face, neck, shoulder and arm and collar bone. Did fiour years of Tamoxifen, no chemo or radiot. Now getting pain in collar bone at times even without headache. Wonder if this could be a symptom of spreading breast/bone cancer.