Hi.. Sudden toothache can be due to sudden injury to tooth like bitting on a hard food or something. You can take an antiinflammatory medicine considering your drug allergies which will help in reducing inflammation and pain. If pain has exaggerated that is suggestive of decay in tooth which has reached pulp of tooth. In both the cases we need to examine and take a X-ray and check the status of pulp depending upon that we can decide for course of treatment.

Your tooth pain can be due to caries(decay of teeth) reaching to your pulp(nerve and blood vessels) or it may be to severe wear and tear of your teeth..there may be other reason for your tooth pain too..for temporary relief you can go for over the counter pain killers but for a more definite treatment it would be better to visit a dental surgeon.