Severe pain and itch

the lower part of the outside of my vagina is really sore, feels like imflammed

I figured it was because I wear thongs and stuff and I accidentally pulled my pants up too high and just made myself irritated

but after a day it got really itchy at times and super irritated, I've been wearing loose underwear but I wear jeans for work so idk it's been bothering me

could this be an std?? I'm 17 but I haven't had sex in almost 2 years

update: feels like theres swelling too should i call out of work?? it hurts really bad now