I have put this in 'General Symptoms' to try to reduce the risk of bias that might occur if it were placed in 'Skeleton, Skin, Muscles, Hair, Teeth, and Nails'. If you are pacing and resting very strictly so as not to get myalgia, or are unable to be active due to the severity of your illness, but you know that you would suffer this symptom if you used your muscles more, you should answer 'yes'. Please vote only if you have ME/CFS/SEID that is not in remission. EDIT: Added on request: This site describes myalgia: There is a wide range of types of pain, and I think you should answer yes as long as your pain/tenderness/etc is worse than before you developed ME/CFS/SEID. Tenderness presumably leads to pain when the body part is touched or used. My own muscle pain is a dullish ache.