I don't understand how a mammogram and ultrasound that show a lump would be considered normal.  It is important to find out whether a lump is benign or cancerous.  Fortunately, most lumps do turn out to be benign, but so far there is no way to tell for sure from a mammogram.  It may have been possible to get the same information from a fine needle aspiration, which would have been less invasive.  But I'm not your doctor, and I don't know the size and position of the lump.  If your doctor suggested an excisional biopsy, he probably had a good reason to think that it would be the most effective way to find out if you had breast cancer.  Call the doctor back about the pain; after a month you should be healed.