I have jaw cramps that started this fall (about 17 months after the end of radiation). I find they are helped by heat (I have one of those neck wrpas you can put in the micorwave and when it's hot, instead of draping it around the base of my neck I hang it over the top of my head and the ends come down to right over the jaw. I hold them to my face for 2-3 minutes every morning and evening). Also I think they are related to my trismus, they often are bad in the morning after the first couple of stretches I do with my therabite (which stretch some of the same muslcesl that get styretched in a yawn)but if I don't let them deter me and keep stretching throughout the day, I don't have them ever at the end of the day.

Nelie