Me and my boyfriend have had sex about 1-3 times a day for the past 9 months. But recently over the past month or two there was one occasion where the area between my anus and vagina would be sore and it would hurt to even touch it with a penis so I couldn't have sex. Then it went away for a little while after we didn't have sex for a few days but just a few days ago the feeling came back? Why is this happening? What is causing this?