I've stopped taking methimazole 12 days ago because of the strong side effects (hives, joint/muscle pain, dry throat). Though these effects are lessening, I wonder how long it might take for them to be completely gone.
I know you posted this long ago, but what was the outcome of your pain? My son is dealing with hives/pain, Etc like you described and we stopped Methimazole a week ago, hoping for improvement soon!