What Is The Reason For Breast Tenderness?

I had a partial hysterectomy still have both ovaries in december of 2010, its been 7months now I am experiencing Breast tenderness pain i never experienced , I had a mammogram in May of 2011 no abnormalities does anxiety cause me to have tenderness for so long my mom died 3weeks ago from cancer of the lung and breast does anxiety cause symptoms of Breast or cancer or is it my Hormones causing breast tenderness all they time