It's not at all unusual to have some swelling,pain and bruising when an excisional biopsy is performed.Some nerves can be damaged during the procedure and the pain can take quite sometime to subside.
If you are running a fever or notice increased redness and swelling at the incision site, it could be a sign of an infection and you should contact your surgeon as soon as possible..
If you are sure that no signs of infection are noticed,and the incision site is well healed,then the pain should gradually subside in due time,but not worsen.
You could apply some warm compresses, gently massage your breast, wear a good supportive bra and try not to lift heavy things.You could also take some OTC pain killers,like Tylenol to help ease the pain.
Hoping that you'll feel better soon and that your biopsy results in benign findings..