One presumes that this is a recent problem and not one that that has recurred over months or years.
As the cultures have proved negative, then there is no place for antibiotics.
Take Ibuprofen for the pain 400mgms up to every six hours if necessary and drink plenty of fluid....water or fruit juices, milk etc.
It has been said that Cranberry Juice is particularly efficacious...........try it although i am not convinced.
If this persists, then see you GP for further investigation by a specialist.