What Causes Pain In Breast At The Biopsy Spot?

Hi i have a core needle biopsy done four months ago, i had a pain after a while but then it was gone, now since last couple of weeks i am having sharp pains in my left breast where i had a biopsy done, should i be worried about that. I do exercise every day for one hour (walk) and i watch what i eat i thought this might help in answering my question. Thanks