Don't Feel Penetration Pleasure

I also share this problem. I'm seventeen, lost my virginity a year ago, but have been masturbating for quite a few years. Through my own clitoral stimulation I can feel pleasure but often it gets intense and suddenly dies down and I just feel tired - I sometimes persevere and keep masturbating, but the feeling is gone. I cannot give myself an orgasm. I've hard three sexual parters and none of them have been able to give me an orgasm, through fingering, oral and actual intercourse. Sometimes when I'm on top I get a weird gurgling sensation in my womb/stomach area and its uncomfortable (is that weird?) I seem to crave penetration but when the penis is inside me I feel very little - no pleasure, just the fact that it is inside me, and sometimes pain. I have tried many positions; some of them only hurt. I've used lubricants and sex toys - we used a vibrating penis ring to stimulate my clitoris and I seriously could not feel any pleasure from that. I recently bought a vibrator and it was highly recommended - however, like a penis, I can just FEEL it but derrive no pleasure, even when on full vibrate. The guys I've been with have all tried their best and put a lot of time an effort in. The weird thing is that I do have some libido - I want to have sex! I just wish that I could actually feel something! I'm scared I'm broken somehow. :/ I might have to post this on a variety of forums but I'm scared I nobody will have answers. 


... Just been reading some of the other threads. So some people also get the same pain when they sit up straight (I'll go get a chlamydia check as I just read it might be a symptom  , its been a while since my last check)