The time to worry if it's CFS myalgia is if the muscle and/or joint pain is all over. The brain is processing all inbound somatic signals as "pain", again as a misguided immune response. If the pain is more specific or localized, it's probably a true somatic defect, and needs to be addressed specifically.

I take 30mg doses of Oxycodone every two hours during waking hours. I cannot function long without it, not with this much pain. I can fight the pain mentally, but that doesn't leave much for productive work.