My left breast is constantly sore, the kind of soreness that you get during your menstrual cycle but just in one breast. The breast feels harder and bigger than the right side breast also. I do believe that I am in the peri menopause and have googled if this can happen. A lot of sites say that this can happen in one breast but as I had breast cancer six years ago in the other breast I am a little worried. Has anyone had anything similar or know if this is a symptom of the peri menopause? Grateful for any responses.