This is just something interesting I discovered yesterday. I had stopped taking NSAIDs because they don't work and just upset my stomach. Have been having bad PEM the past week, with severe muscle aches. Then, on top of that, my time of the month came along with terrible cramps. I decided to take 4 ibuprofin, like I used to, just on the off chance it would help. Result: it greatly lessened the cramps, but did nothing for muscle pain. The only conclusion I can draw is that there is something about pain from PEM that is very different from other types of pain. Has anyone else had this experience? I don't think it's a severity issue because I get VERY painful menstrual cramps (like curl up on the couch and cry). Are there pain medications that are specifically better for pain related to ME/CFS?