If the pain is due to an infection developed due to carious tooth ie tooth with hole in it then there are only 2 options.  If you want to save the tooth get a Root Canal.  Otherwise get it removed which is cheaper   . But you are loosing a tooth and the supporting area like the bone will shrink over the years. Also the adjacent teeth will tilt or migrate to that area too. So a removed tooth has to be replaced which will be more costly. Either way get a consult and opinion from a dentist who can visually check and let you know what can be done