Had a root canal 4 yrs ago. still hurts to brush, bad head pressure, sore jaw and sinus feels stuffed. should i extract it?

Root canal pain: See your dentist for x-rays and an examination. The pain may be from the tooth that had the root canal ( unhealed or recurrent infection, fractured tooth), or from a surrounding tooth.

One thing at a time: As far as the root canal get another opinion to see if the periodontist got all of the roots. If not complete the root canal. If yes than check out your sinus' and also see a good dentist.

Reevaluation: Have you not seen a Dentist for 4 years? This should have been corrected years ago. See Endodontic Specialist to evaluate and possibly retreat. Filling may be too high. Tooth may be fractured or infected. Need reevaluation by Specialist.

See your dentist: Good to see someone else from Toronto on here! I would definitely get this reevaluated by your dentist. He/She will perform a few diagnostic tests and probably take a radiograph to figure out what is going on. You may need the root canal retreated.