What Causes Redness And Itching Of The Labia?

Hi, im 18 yr old and have been having sex since i was almost 17. back when i was seventeen i started to get inflamed and red, sometimes just one side of my vagina. i think its called the labia. and it would hurt for like a day and would hurt to pee. but i was to scared to go to the doctor. i had a break between boyfriends and when i started with my new boyfriend this year it didnt happen, until a couple of nights ago, and it hasnt gone down and now its really itchy! and i put ice on it but nothing has happened. its like 4:30am so i cant see a doctor.