6 year old with urine pain please help

Is there anyone who can help me?
My daughter is 6 years old and has had very severe pain on urination for 3 months and has pain in between. She has seen a urologist who has done many tests on her which have all come back neg. She was diagnosed with a non specific urethral syndrome and put on oxybutymin, this is not helping though.She has had 4 courses of different Antibiotics although she does not have an infection and I have now just been to see a natrupath who has given her a herbal medicine that as yet is not working but I suppose it is early days as she has only been on it 3 days. I am getting very desperate as there are only so many times you can listen to your child cry in agony when she pees, before you start to get very depressed. Please, if anyone can give us any help I will be eternally grateful. Thanks Tweet