Why would my vagina be so overly sensitive and what can be done about it?

Hi, it's Trish. I am 22 years old and the problem that I'm having is that my vagina seems to be overly sensitive, I believe, but I have no idea what the problem really could be. I experience a weird feeling in my vagina whenever I put something hard in it and bring it in and out. I tried vaginal masturbation for the first time using a marker this morning, which is new to me because during the rare times that I do masturbate, I just rub my clitoris, but I had to stop using the marker because I simply couldn't handle the feeling. The feeling itself is too hard to describe; it feels both pleasurable in a way but unbearable at the same time, if that even makes sense. I'm a virgin, so I highly I doubt I have an STD or some sort of infection and in any case, my vagina seems to be mighty healthy overall because it lubricates well, doesn't itch, doesn't smell, and doesn't emit any type of unusual discharge. I am just afraid that if I do finally get a boyfriend and have sex with him, I definitely would not be able to handle it and would have to pause for a while because of this problem, which could definitely turn him off. Is this normal or should I see a doctor?