Persophone, I am really sorry that you had to go through the pain of a core biopsy. They certainly are uncomfortable, and very, very painful. However, to add another perspective to it - mine showed a pre-cancerous lump which they were able to remove before it did any harm, so they can be worth it.

I am now checked every year with a mammogram, u/s and examination by my breast surgeon. This past check they did a fine needle biopsy on something which showed up on the u/s and turned out to be nothing. I think they are "jumping at shadows" due to my history, but it is the better of the options..