Hi Neil and Welcome! Sorry to learn of another fibro sufferer with unbelievable pain. I've noticed an increase in symptoms after eating and came to my own conclusion that our bodies have to work harder to digest the food, thereby causing more pain. Does that make sense?

As for your reaction to fever, increase in temperature.....my response is different because I also have multiple sclerosis and any temperature raise brings out the MS symptoms which are similar to fibro. However, instead of feeling stronger, being heat sensitive, I end up feeling like the proverbial "wet noodle".
Both of these auto-immune things are a mystery and all we can do is treat the symptoms, avoid the known triggers and live the best life possible. Take care.....