When you have a UTI is your vagina supposed to b sore?

Not vagina. Urethra, urine tube between bladder and perineum, may be sore, especially the opening. It lies right next to & on top of the vagina, which can make you think the vagina itself is sore. Std needs to be ruled out if your vagina really is sore. Good luck.
UTI and vaginal pain. Typically uti's can cause bladder pain which may be perceived as vaginal pain or there may be some discomfort at the opening of the urethra which is between the clitoris and the vagina. Deep vaginal pain generally is not associated with a uti.