My Daughter, Age Ten, Has Suffered For Weeks From Burning

My daughter, age ten, has suffered for weeks from burning urination, cramping during urination, intermittent burning at other times, intermittent frequent urge to urinate without success, and intermittent nausea. She tested negative for a urinary tract infection. She is not red on the exterior. Her appetite is fine and so are her bowel movements. Today we had a renal ultrasound and it was clear. What is this???