It burns sometimes when i pee but i have no std why?

Dysruria: Burning during urination can be caused by a number of problems including: urinary tract infection, STD, crystals or stones in the urine or mechanical issues related to irritation of the opening of the urethra. Urinanalysis with microscopy is a simple test of the urine that can shed some light into the possible causes

Burning micturition : This could be a sign of urinary tract infection, you need to see your doctor, have a routine urine analysis & a urine culture . At the mean time drink plenty of fluids including cranberry juice that helps in washing out bacteria from urinary tract. Feel better.