You'll need a day off, but that is all. Breast biopsies don't take terribly long to do, are done generally with a just a local anesthetic. When I had mine, they did give me something to relax during the procedure (but honestly it probably wasn't necessary). It's uncomfortable mainly because of the bizarre way you have to lay for the procedure more than the procedure itself. It was not painful afterward really and I was back to work the next day.