Me and my partner are sexually active, we use condoms. But everytime I use the restroom after having sex my vaginal starts to hurt like a burning.?

Friction or allergy? Could be from the friction or allergy as the tissue at the opening , and just inside urethra is very sensitive and the tissue inside the vagina can be sensitive. Many times if the condom has the spermacide, that can be irritating. I would try condoms without spermacide. If it still hurts you should see your gyn for a proper evaluation.