Are muscle aches a common side effect when quitting smoking cigarettes?

Yes: Muscle aches are not invariable in people who are trying to quit smoking, but they do occur. Nicotine is a muscle relaxant, and in withdrawal muscles can get tighter, causing pain and sometimes even spasm ("charley-horses"). Hot baths or hot backs, a heating pad all may help. If they are severe, nicotine replacement with patches, gum or lozenges will do the trick.