dehydration can lead to burning when you pee. If you have had any type of unprotected sex as of late you should test. It would put your mind at ease.
Ok... RISK: Have you had unprotected oral, vaginal or anal sex? That would be a risk for stds. There are other things that are not std related that can cause your symptoms.
did you have any risks?
if you had a risk NGU is a risk factor.