Why does it burn when i pee after my period?

External irritation: You can get urinary symptoms after a period if you used sanitary napkins and have any chafing of the vulva, or just form the ph change in the vagina associated with bleeding, which can sometimes allow yeast to grow for a few days until your body gets back to normal--this can cause burning of the vulva if urine hits it. You also need to make sure you do not have lesions (sores) "down there!