1. where do i aim head or neck?
I aim for where the neck meets the body (where the feathers start)

2. what kind of choke i have a modified and a full and 1 other kind i think i have the modified on at the moment so i was wondering if you could tell the best one?
You should try different loads (different size pellets, 4, 5, 6) 3" and 3.5" and different choke combos to see what gives you a tight even pattern consistently out to 40 yards. Not all after market chokes are very expensive, but some are. Every gun shoots different, you'll have to see what yours likes.

3. are there different kinds of turkey loads if so what is your recommended type? I like Hevi Shot (Hevi-13s in 3.5" #6 2.25 oz is what patterns best in my gun so far.)

4. i dont NEED a scope do i?
You don't need a scope, but you should probably have some kind of open fiber optic sights or a scope. When those patterns get tight, it helps you hit where you're aiming. Better open sights than a bead, but to each his own.