hello and welcome to hcm forum,
i am glad to answer your query, according to the dental history presented by you it seems that you have been suffering from a TMJ
problem for quite a while, and the pain in jaw is usually associated with it, headaches
are also sometimes associated with TMJ problem, therefore i would advise you to see a dentist(oral surgeon),
clenching of teeth is related to stress
or may be due to other reasons as well, in order to rule out the cause, a dentist need to check you clinically, therefore, it is best to visit your dentist soon.
i hope i answered your query,
i wish you good health,