Chilla rean't the word...but,, to answer your question..yes. Sometimes the chills last for hours. I thought it was withdrawl symtoms from the meds. Turns out,,the system in the body that regulates our internal temp, has been disturbed..as such. The only relief I find from it is to drink somethng quite warm like Hot chocolate because of the caffeine that helps raise the body temperature. Usually after an hour it subsides. I never know when they will hit. Usually occurs at the most inconvienent time. But..what else is new. A side arm of the beast I guess.