I am an 18 year old virgin. I have used tampons for years and I have noticed something inside of my vagina. I'm not quite sure how to describe it, but it feels like a small (.5cm diameter) cylinder or tube dividing my vaginal cavity into two sides. On one side, I can fit only super slim tampons without pain and on the other I cannot fit anything without excruciating pain.

Earlier this week I was trying to take out a tampon and the string got caught on the other side of this 'tube'. It was extraordinarily painful and it was only after I threaded the tampon string to the other side that I could remove it.

Anything more than a super slim tampon is extremely painful and I have been using them since I was 13. Any help is greatly appreciated.