Just read your post about having chills and also failed root canals. I, too, have had root canal problems. In 2006, I had to have three procedures done on one tooth and it's still not totally "dead" and am scheduled to have another root canal on a different tooth next week. Right now, I'm fighting an ear infection and once again the dreaded chills have set in...no fever, just chills. I've been battling this on/off for a few years now with no luck in finding out what's causing it.