vaginal pain during sex

[mixedclash.livejournal.com]

For the last couple of months or so, when I lie in certain positions (missionary, for example) during sex, it hurts a lot. But if I lie on my stomach, it doesn't hurt so much. I talked to a nurse (can't see the gyno until the 19th), and she said I may not be getting aroused enough and to start having more foreplay and breaking out the K-Y. I did and it's helped somewhat, but not entirely. I have no idea what it could be. Any thoughts?

description of the pain: My vaginal walls and the back of my vagina hurt with penetration in some positions, even when I'm lubricated.