Thank you so much David, it's good to hear that the chills are normal. We thought it was withdrawing from the pain meds to quick so put a 25 pain patch back on (he had been on 50's) Soon after we put it on the chills went away but his throat started tightening up and last night was back to the heavy mucus and was up several times during the night to gargle, and had a hard time getting oatmeal down this morning. What a see saw, so have you heard of the fentonal causing this? We took the patch back off this morning so we shall see.