Many children have been sick of late from similar symptoms I think it is allergies, caused by environmental issues .If you scroll down on this site you will find similar posts, doctors dont know and parents are mystified. I hope you find some answers Good luck
Google periodic fever syndrome. It seems some kids do have this situation and they grow out of it around 10. I don't know if your daughter has this but it is worth looking into it. The Cleveland clinic is doing a lot of research on it.
Is her doctor not giving you any ideas? Have they looked for an infection? I've been reading about strep lately and people typically only think of a sore throat with that but in truth, you can have strep anywhere in the body. Our children's hospital is now screening situations like your daughter for a step infection that is atypical.
I hope you find answers. I've found we have to be our kid's advocate and keep on searching. Many docs do love a medical mystery but some would rather not deal with it. So, being that squeaky wheel that gets a doctor to search for answers is key,
Hopefully she'll start being fever free but the things I've read on periodic fever syndrome are really interesting.
good luck!