Okay. To review, you have a single sore tooth, no swelling or inflammation, no recent cavities filled or crowns placed but you do grind your teeth - there's a good chance the soreness is due to grinding. It's also possible the grinding is just a coincidence, in which case, a cracked tooth or an old, cracked filling is to blame. An injury to the tooth could also be to blame. For example, an old sport injury could have injured the tooth, its nerve or its blood supply so that over time, the tooth becomes more sensitive. See your dentist.
Just one more question.
Do you take a medication for osteoporosis or other bone disease, such as alendronate (Fosamax), risedronate (Actonel), ibandronate (Boniva), or the intravenous medication zoledronic acid (Zometa or Reclast)?