What Causes Vaginal Soreness And Burning Feeling?

i have been with my partner for about 6 years now and we have only been sexual with eachother we have a 11 month old son and we just had sex monday and it wasn't any different until the next day i was really sore in my vaginal area..then the next morning it would burn when i pee and it really hurts to walk and sit down in my vagina area i dont know what this could be?