Hi Lostone.

It is possible to have pain in the area that you describe from herniated lumbar/sacral nerves.

L5/S1 supply the bowel and bladder, while S3/S4 are more related to sexual function.

Here's a chart that explains the nerve distribution in a bit better detail:
http://www.disabled-world.com/artman..._picture.shtml

From what you say, it sounds like fear is a big part of the problem that you have. Anticipation that intercourse will hurt is often enough to cause the vagina to tighten, even spasm, which in turn causes more pain.

May I suggest that you discuss your fears with your GP or OB/GYN. Although it may not be a total 'cure', relaxation exercises, or a muscle relaxant, may be all that you need to overcome this in the initial stages.