Well if your a female it could be many things. You didnt give a lot of information. Like the last time you had unprotected or protected intercourse.
Reasons for vaginal burning could be caused by:
There are bacterias in the vagina that are supposed to be there but having the wrong ones enter and grow can cause vaginal burning, itching, and a smell. But not necessarily all of them.Chlamydia
Chamydia is spread through sexual contact and can cause all of the same symptoms as bacterial vaginosis plus sometimes discharge.Gonorrhea
Gonorrhea has basically the same symptoms as Chlamydia.Genital Herpes
One of the fastest symptoms to emerge when you contract herpes is a burning sensation followed by redness and blisters. (But not always)
Yeast infections are very common and a burning sensation is often a symptom.
Irritation or an allergic reaction
There are many things that can irritate a person as well as many things that people are allergic to. Soap, and medications are often the most common.