Posted 9/22/2011 6:47 PM (GMT 0)
Sounds a lot like a kidney stone to me, also. While the urine blood test might show there not being any blood, that may not be the whole story. Usually an X-ray or IVP/CAT scan will show it.
If it keeps hurting, I'd get a second opinion.
And like mtgman said, drink lots of water!