I suffer with aching legs, generally when I am tired and it was probably referred to as growing pains when I was younger. Over the weekend I had, what I can only think was a strange virus, where the whole of my legs ached and then on Sunday I had the most awful back ache over the whole of my back, in my hips and the tops of my legs (I also had a temperature). Paracetamol did help. Your daughter may have something similar, there are some funny things about. Hope she feels better soon.