im very worried because my partner and i had unprotected sex for the first time about one month ago. we only had unprotected sex half of the time tho and then he put on a condom. anyways so about 2 weeks ago i noticed if we had sex multiple times during the day it would burn after to go to the washroom. i noticed the other day i had an open sore right under the opening of my vagina. it only hurts if we have multiple sex in one day... if we do it just once im fine... i was wondering could this be a sign of an std? or could it be something as simple as me cutting myself while shaving and maybe it keeps being reopened during sex or maybe a bit of tearing from not using lubricated condoms?? im really worried :S i should also mention that i dont have any other symptons associated with any other stds thats ive looked up.