Why Is It Burning While Urinating?

early this morning i masterbated ... && later on about a hour ago i choose to take a shower like i normally do , but it was time to shave , soo i shaved && i now have this buring inflammtion feeling on my inner labia an it only burn when i pee , not wipe && if i wash with soap not with warm water , this is the very 1st time this happen to me what should i do ? ; what is this ?