"我牙从来没毛病,这次头一次疼,还是上火引起的。。。" you got infection
previously in your tooth, and the worms are not active when you are healthy,
and you don't know that. However, when you are under stress (physically,
mentally) your immune system goes weaker, and worms are getting active and
put you in the hell. so go to see a doctor to check the infection to solve
the problem once for all. Regally to check the teeth and fill the decay
immediately to prevent severe problem. Personal dental insurance is
available if you don't have one provided by employers.