Why does it hurt?

Angel

I don't know why but ever since I was a teenager whenever I've been fingered it hurts. I figured when I was younger it was because I was a virgin when I dated my ex but I've been having sex with my husband for going on three years now and even whenever we try fingering it still hurts. And this was before I had my daughter and my body and hormones changed and I used to get really, really wet. His hands are clean and his nails are short and I don't have any sort of infection. I just decided not to try anymore because I don't get any pleasure from it because of the pain. Is there any sort of medical reason or something that fingering could hurt me?