I want to know why girls bleed after or before intercourse is over?

Can a girl get pregnant if she's on top with no condom?

I would like to know if shallow penetration can get one pregnant, or does only deep penetration make one pregnant?

My boyfriend and I have been going out for a year and are really in love. We started to have sex a few months ago and everything was going great until we tried doggy style. When we did it, it hurt a lot; it actually hurt so much that my knees buckled. Ever since then I've been scared to try it again because it felt so awful for me, which really sucks because my boyfriend liked it a lot and it would have been great if it was nice for both of us.

Now even when he's on top, if he thrusts really hard and goes in deep, I get a shooting pain like up my spine and all over my tummy, at one point i felt like pressure and a popping feeling around the upper middle of my tummy. Mind you, this is only during deep penetration. I don't really know what is up. It would be great if you could give me a little advise on what's happening, and what I could do to prevent this! Thank you so much!