Does she have any urinary complaints too- like pain while passing urine/ increased frequency of urination etc?
How are her bowel movements? Does she pass soft stools daily?
Its better to have urine microscopy done to rule out Urinary Infection- which is quite common in female kids.
If pain is severe as you have mentioned- ultrasound
abdomen will also help.
Hope my answer helps you.
Wish your daughter good health.