Extreme pain when trying to penetrate.

I’m a 24 y/o petite female, and even from a very young age I’ve never been able to comfortably fit anything in my vagina. I’ve never been able to put in a tampon without experiencing extreme (yes extreme) discomfort or pain. I don’t know how to describe the pain other than a stinging sensation that’s excruciating for me. I’m 24 now and I’m still a vaginal virgin. I bought a normal sized dildo and some lubricant and still can’t put it in without experiencing it. I’ve never had my Pap smear because of fear of extreme pain. I’ve done a lot of research and it explains that it could be a serious condition a muscle contraction and I honestly don’t know which one. It also tells me that it could be from stress (yes I’m an SA victim) that causes muscle spasms. I’ve had to turn so many guys down because of this and the last time I tried was a couple of months ago and it was genuinely so embarrassing, I feel like I wasted his time. I really want to experience the pleasure of sexual intercourse without the pain and discomfort. I’m super nervous about talking to my doctor about it. Any and all advice welcome.