What Causes Swelling And Itching In Vagina?

i have burning, redness, swelling, irritation and itching of my vagina. I thought it was a yeast infection so i tried monistat but as soon as i inserted the medicine it started to hurt even more, it bothers me so bad that i have to sleep with ice between my legs. I have no discharge and no smell. and I don't have urgency to go pee, sex hurts however. But it can't be an STD because I have never had sex without a condom. Please help! I dont know what it is. Should I go to the hospital?