Try a combination of masturbation and a little porn. Downlaod something you may enjoy that turns you on, there are varying levels of raunchiness frmo soft porn to more hardcore depnding on your taste. The softer ones tend to be more erotic..
I think if you try that you may find you will be more successful. Also try and relax and not place too much pressure on yourself to climax, it will happen.
Another thing you can try that apparently is very effective is using one of those extendable shower heads that have the pulsating effect. My girlfriends tell me that is the only way to fly ;)
regarding the pressure and discomfort, many women have this problem, you are not alone. You can try various positions to try and find some that you will find more comfortable and enjoy. Try side to side for example, that can be fun. Also make sure you are wet enough, if not, use a water based lubrication like ky or even better astroglide, both of these provide adequate lubrication that may easy some discomfort.
Make sure your partner knows your discomfort and get him to be a little more gentle and not pound you as hard as he usally does, sometimes doing it so he doesn't ram into your cervix with each thrust can be all that is needed to releive your discomfort. The cervix can be very sensitive in some women and they dislike the sensation of the penis hitting that spot. Other woman absolutely love that sensation....
But try the porn/masturbation combo and the pulsating shower head and I am sure you will find what you are looking for! No woman should go without the release of an orgasm ever! ;)
good luck to you....Keep us posted.