Hello~Candida or Fibromyalgia are two health issues that came to my mind. Both can cause the symptoms your daughter is having. Here is a link to a good site regarding candida: https://www.thecandidadiet.com/candida-symptoms/
Fibromyalgia can also cause these symptoms, especially the fatigue and pain.
I would tell her to avoid all sugars, wheat, yeast and glutton products, in doing so, this might help some of her symptoms. Make an appointment with the GP and ask for a test for Candida, this is usually a stool sample and for some blood work to rule out fibro, although, the best test for that is when the doctor presses on certain "trigger points" if these hurt, then it is very likely fibromyalgia.