Suggest Remedy For Pain In Vagina After Intercourse

hi i had unprotected sex with my bf,immediately after the intercourse my vagina was very painful, i felt like i had an inflammation. then a day later, i got back, we had sex again and hours later the pain came back... i dont understand why, then within 28 hours i had a morning after pill (escapelle), a day later my vaginal discharge changed to an odourless yellow colour. what could be the problem?