Hi doctor, I am 30 years old, I have this pain that has gone on for the past two weeks in my right shoulder area through to the upper back, sometimes it feels stiff, numb or even sharp. the same sharp pain I experience it in my breast . when examining the breast , there is nothing unusual comparing to the left breast but touching near the nipple inside area, there is this sharp pain, could that be cancer? I last breast fed about 3.5 years ago