Urine troubles :(

So my daughter who is 5 years old has been complaining every time she has to pee. She said it hurts "down there" I make an appointment the Doctor had us do a urine sample. Everything came out clean. No UTI, however I've noticed its not when she pees that it hurts or burns down there. She knows she has to go, but when she tries to go it won't come out and that's why she says it hurt. I keep telling her (and myself)that it will go away and maybe she's still trying to figure out her own body? I hope it's nothing serious...what could this be?