I would continue to pursue with the doctors; if you're having pain there's obviously something causing it. Often doctors can see a negative test and think of it just that and not pursue anything else. My concern is that you initially had 2 positive home tests and have not had a period yet. I would consult with your primary doctor and explain to her that you had 2 positive home tests and you still havent had a period. She might order yet another test, or even a blood test. From there she might refer you to a gynecologist to find out why you havent had your period. Tell her your symptoms and of your pain. He/she cannot deny your symptoms or your missed periods. If this persists, there are other things this can be, but first lets start with this. If you can see a gynecologist, she may be able to help out. Mention all the symptoms you mentioned here and the 2 positive tests you had. Definitely persist, even if right now the doctors don't beleive you. Often times you just have to present things in a different way to them and know how to work the system :) Good luck and keep us posted.
Sara RN