My advice is educational rather than a formal medical opinion, but I would have your daughter evaluted fully for these symptoms - there may be a mechanical problem or growth in the leg causing the symptoms and for instance serious disorders such as tumors should be excluded by an imaging/MR study as they can occur in this age group. A good examination by a physicain/orthopedist would be a good place to start and they could better decide whether more testing is indicated.
Good luck
Check the spine too. It could be sciatica. I get that too, feels like a horrible cramp running from the thigh to the leg.
ask your pediatrician to do an xray......has he checked her for muscle spasm? doess she do sports? good luck
Definitely have an Xray of the leg as well as the hip performed as soon as possible. Rule out the most concerning problems first (like small fractures, hip joint degeneration, etc.) and then go for other screens, looking for sciatica, performing possible EMGs, blood work, muscle testing etc.