My left jaw has been hurting and my gum is sore around my tooth on that side. what could this be? and how can i stop the pain?

Infected tooth: or an abcessed tooth. Take otc nsaid and also apply otc oragel to the gum after gargling with and antiseptic oral solution. In the mean time call your dentist.

See a professional: See your Dentist who is trained to diagnose the source of your pain (could be tooth or gum infections) and can then provide the best treatment. This is not a DIY project, you need to see someone with the training and experience to examine you and then answer your questions. Call NOW. Delay will only allow the infection to spread.