I current have tooth ache in my upper left 4, premolar tooth, i had rct on it around a year and half ago and has always caused pain on and off but would go months with no pain then 2 days constant etc. I had tooth ache just over a week over just a dull ache had tooth xrayed no infection around the root no black area on the xray and root filling is to the apex. Dentist said my sinus is close to the end of root so may be affecting it, feeling pain when u have headache etc more than usual. I had a course of amoxy 7 days. And now today my pain is horrible everything hurts on my left side upper quad every tooth hurts. Im not sure what it could be. Ive work at a dentist so i no i have good oral hygiene as seen the effects of poor oh. Some afvice would be good