Is it normal i can ejaculate and orgasm 6+ seperate times < 5 minutes

I am a male 23 years old. I used to masterbate alot in my teen years but stopped for a couple years. I started back up like a year ago an ever since i have had the ability to orgasm six or more times in less then five minutes! Thats not all i can wait about ten minutes later and do it all over again. I have hit 18 orgasms an ejaculations in less then an hour an i could do more but the orgasms start to hurt an by number 16 barely any semen comes out... is this normal??