Ckis it normal to freeze up before having an orgasm?

So i've never had sex but I do masterbate alot. I've had plenty of mind blowing clitoral orgasms but I could never achieve a vaginal orgasm. Ive worked with different vibrators and no luck! Right when I feel like I'm hitting the g-spot and am about to orgasm my lower body freezes up and my vaginal muscles tense up hardcore around the vibrator. I also kinda feel like I'm deaf for a couple of seconds in this moment and then my "near orgasm" slips away and I can't reach it...but I do cum a little bit. I don't think this is an orgasm because I know I could reach a "higher point"; I could feel it. I don't know if I'm just not relaxing enough to feel it or what. I hate that I go numb/freeze up down there. I'm so close! I've also been trying to squirt (I've researched that anyone can do it, but people squirt differently; some less..some more). I heard you have to "let go" to do this. I've been trying to but I just can't; I don't know if that's the main problem or not. Overall I just want to know if it's normal to freeze up before a "possible" vaginal orgasm and if the problem is caused b/c of too much tension and too little relaxation. And also if relaxation is achieved, could squirting finally happen?! Has anyone had similar problems/details. Thank you