Why do I keep on biting the inside of my left cheek when I am sleeping? I have had this sore spot (sometimes more painful than other times) for a couple of years now, at least that long if not longer. It never goes away. What could I possibly be dreaming all the time that causes me to grind my teeth in such a way that I keep irritating this spot which is therefore never allowed to heal? Strange. Probably all my daily frustrations getting in the way and trying to express themselves at night. Grind, grind...