Expert Q & A Answers About burning with fingering

My girlfriend has a burning feeling when she urinates and when I masturbate her...what’s wrong?

For about a month, my girlfriend has been having a burning feeling when she urinates and when I masturbate her. I do have oral sex with her and masturbate her, but we haven’t had intercourse. It shouldn’t be an STD because we’re both virgins, right?