Can't orgasm...

Ok so here's the deal. I'm 19. I'm not a virgin but any time I've had sex we never finished cause we didn't have a condom so I never let them finish in me so I never finished. My boyfriend lives 8.5 hours away so I never see him. Instead I use my vibrator. But I'm afraid to orgasm. Everytime I get super close I stop cause I feel like it's starting to hurt or is going to hurt and I'm not a big fan of pain. I want to orgasm so bad and experience that. But I'm scared so bad it's going to hurt. Help?!?!?