Had a root canal on wisdom tooth. Pain for three weeks. Pain reliever Round the clock. Pain in cheek and jawbone. Half of face with teeth in pain.

See dentist. return for follow up with the dentist who did the root canal or get a second opinion. It is possible on lower teeth to get inflammation in the nerve canal that runs inside of the jaw bone. This pressure will cause everything along the whole side to hurt. Seek follow up care.
Extraction. If you had an unsuccessful root canal on a wisdom tooth, the next step is likely an extraction. See dentist. You may be referred to oral surgeon. For best results with wisdom teeth, make sure you are evaluated and treated by a board certified oral & maxillofacial surgeon.