I'm sorry you are having this pain! And can't find answers. I assume you've had a regular pap smear which is scraping of the cervix to check the cells there? That's what they do to know if you have pre or full on cervical cancer. Genital warts usually don't hurt so wouldn't suspect that. The cervix can get inflamed and would imagine this hurts and it can do this because of allergy. Have you tried different products of tampons? Thee is also something called cervical erosion. It can cause pain. It's caused by a variety of reasons from ph problems, to trauma, to too much estrogen production to chronic infection, etc. It doesn't hurt in most women but when it does, they treat by caution with the cervix, sometimes laser surgery and sometimes cauterization. BUT, they normally can detect it. that your doctors are not finding anything when you are there is probably a GOOD sign. Perhaps it is an inflamed cervix?
Never give up asking and searching for answers. I wish there was more I could do for you.