J.G.
You have received a lot of responses, but I wanted to respond to tell you not to worry just yet. Many breast lumps are benign. I had a fibroid on the bottom side of my breast a few years ago. (A fibroid is a mass of tissue caused by increased levels of estrogen.) It was about the size of a small grape and moved around when pressed on -- kind of rubbery feeling. You should definitely get it checked out, but if it is a fibroid they are dealt with in a simple out-patient surgery and have no connection to an increased risk of cancer.