Hello,
Welcome to the ehealthforum and I am glad to help you out. The soreness that you are having can be due to the friction to the vagina during repeated intercourse. Symptoms of pregnancy do not appear just after having unprotected intercourse and take some days to come up.
This pressure is due to continuous pressure during intercourse. Avoid intercourse for a few days as it may cause further friction and trauma and take some oral anti inflammatory drug.
I sincerely hope that helps. Take care.