If you're referring to Attack Attack! on their Someday Came Suddenly album, Austin Carlile (also from Of Mice & Men) uses fry screams. It's the technique Melissa Cross refers to in her DVDs as the one she prefers.
It's done by creating a passive wall between your vocal chords (to quote Melissa) and requires very little air. Easier said than done, so watch her videos and some online. It's a fairly quiet scream, unlike what your friends seem to have told you.
Forcing a lot more air will not raise the pitch of this scream. For me it took a while to learn, but if you have fry screaming down consistently, then it's just a process of slowly bringing your voice box up in your throat without losing the sound.
Oli Sykes from BMTH uses a combination of false chord AND fry screams.
If you sound like the "I've got a secret" part from Chelsea Smile, you're actually doing false chords. You'll hear the difference in BMTH's songs. The part where it sounds like he's really yelling is false chords, and the parts where it's a little harder to understand :P are fry screams.
With fry screams you'll be able to hold the screams way longer considering they require very little air.
The way I learned to do it was to sing a note, and then drop it down as low as possible until you hear the individual vibrations over your voice. Then from there, you begin raising it slowly, but keeping the vibrating and not having any voice interrupt it. Eventually, you'll learn what the muscles feel like and you can begin raising the pitch even more and controlling it.
The vocal chords should NEVER hurt. But you will feel some fatigue in the muscles and won't be able to do whole songs right from the start.
I hope I helped. Drink lots of water, and warm up your voice before doing a long song or set.
Also, keep in mind it doesn't have to be loud, and there's a limit to how loud it can get before it's bad for your throat. So be more concerned with the sound than the volume.
Hope I helped.
