Yes - even the shy ones, the very innocent ones, geeks, emos - EVERYONE. In theory a few super-religious guys don't because their church considers it sin - but they probably do it anyway. Many Christians are in favor (see link below).
Old sperms need to be ejaculated, to make way for younger, more active ones; these give a better chance fathering a healthy child. That's why it's so difficult to stop masturbating - it's something males need to do regularly, from puberty onwards; though some start earlier because it feels so good.
Once or twice a day is average for teenagers, though there are wide variations. Have a look at
http://www.jackinworld.com/howto/ht.html
where it is stated that "It's not uncommon for a 13- or 14-year-old to masturbate 3, 4, or even 5 or 6 times per day . . . Just enjoy it and know that in a couple of years, you'll probably throttle back on your masturbatory habits somewhat."
Masturbating is very good for general health:
http://en.wikipedia.org/wiki/Orgasm#Orgasm_and_health
http://www.healthnews.com/family-health/mens-health/australian-researchers-link-masturbation-prostate-health-918.html
This link is very helpful:
http://www.jackinworld.com/bios/bio233.html
Of course girls masturbate too, and guys love knowing that - it makes you seem more like us - more approachable and sexy :-)