Every time my girlfriend and I go to do it she ends up in pain every time.after about 10 min she asks me to stop(which I do because I respect her) because she says it gets to a point where it only hurts her.she says its because she hasn't had sex a long time and she's tightened up.
I know that's it isn't due to being dry and we have used lube and I am very gentle about it but it still hurts her.anyone know why or had any personal experiences with that kind of thing?and anyway to help her?

She isn't relaxed, she is expecting the pain therefore it happens she needs to stop expecting it to hurt and relax try spending more time playing and getting her all chilled out.

What about foreplay? Are you two fondling and kissing before intercourse?
It might help your girlfriend.
I have this problem when rushing into sex, it's better and funner to just take it slow! :)

Might she have some kind of an infection? Thrush can do those things to you at times although the other posters here also have a point.

Infection is α possibility but...

I hαve the sαme problem.. my hubby tαkes it slow or I go on top of him αnd well you know until I get used to it αnd then the fireworks hαppen;)