A sore tooth can be due to many reasons, some of which are; grinding, decay and infection. If pain has come and is now gone, this can be a good or a bad thing, and difficult to assess without having a look. If the pain has gone as the tooth was inflammed from grinding and has subsided, then this is good. However, if the pain was due to a dying tooth and the pain is gone as the tooth has died, then it is very possible to have an infection in the jaw that is yet to cause pain. This is why some people have some pain, then no pain then present with a swollen face.