Can you catch an STI from a virgin?

Can you catch an STI from someone who has never participated in any sexual contact previously of any kind.
I am really worried- I thought I may have a water infection despite not having any lower stomach pain because it sort of hurt to pee and I needed to pee a lot but at my gp she tested my urine and said that it doesn't look as if it is a water infection but she will send my sample off.
She said that it could be due to friction in sex on my urethra which has caused trauma, which I agree is very possible, but my labia are sometimes mildly itchy? Could this just be due to the fact that I recently had sex for the first time without lube and it caused some friction on my labia? 
Also I became sexually active a month ago and had no STIs prior, he was a complete Virgin in that he'd never had any sex (oral, anal, vaginal) or sexual contact before, so would symptoms only just be showing now?