Is it suppose to burn when you wash your vagina with vinger?

I assume you mean vinegar!!! Vinegar is basically dilute Acetic Acid. Of course it is going to burn!!!!! Why do you want to wash in vinegar? Are you trying to encourage conception of a particular sex baby? By washing in vinegar you are lowering the pH of the vagina which is already an acidic environment and so by doing so you are making it even more acidic!!!! Don't do it, it will burn and cause ulceration of the delicate tissues down there!!!!