There are many things that can cause jaw pain, and I am sorry to hear that you are having to deal with this. One of the more common problems among young people without any other likely problems is temporomandibular jaw syndrome, or TMJ. This often originates at the interface of where your jaw connects with your skull, and slight alterations in the orientation of the joint can cause recurrent pain with chewing, headaches, sharp shooting pains, and other common problems with your jaw. The pain or discomfort can come and go, and varies from person to person about how much it impacts your life.
There are many treatments available, starting with conservative approaches such as jaw exercises and over the counter non-steroidal anti-inflammatory drugs (NSAIDs such as ibuprofen). After those approaches have been tried, there are other treatment options as well, ranging all the way to surgery for those who continue to have facial pain. It is important to meet with your dentist
or an ear-nose-and throat surgeon
) or an oro-maxillo-facial surgeon (aka OMFS) to make sure that you really are having TMJ, as other things can cause jaw pain, some of which might be serious. Please see a physician if this problem continues to bother you or you have other symptoms.