I had a steriotactic core biopsy about 5 years ago and it really wasn't bad at all. I remember it was rather lengthy and I had to lay on a table with openings for the breasts ( I was lying on my stomach at the time) and the Dr. worked from below the table injecting a needle into the breast. In my case, the only discomfort I felt was when the needle was inserted and that wasn't bad at all. So don't worry about the pain, because if it is like my case, you won't feel much at all. And that's the truth! good luck!