you havent mentioned your options that you tried. however here are some common reasins for pain.
1. tooth decay
remedy: get an xray done and then you may need a filling or root canal
to solve your problem
2. gum disease
remedy: get a tooth cleaning done and treatment for sensitivity
3. trauma and attrition remedy: isolate the reason and remove it
kindly give me some info about the nature of the pain, how long you have had it, whether you get the pain at night etc