Is it the nipple that hurts, of the main part of the breast? I was talking to another mum today who had recurring pain like you described, but located in the nipple, and she ended up getting referred to the top guy at Kings, and he prescribed a topical antibiotic cream, which cleared it up within 3 days (she had been suffering for weeks). Like Pickle said, worth seeing you GP for sure, and push push push for referral.