Arm Slots

IMO, the biggest issue is going to be that as you get older and face better, smarter hitters....they will learn to recognize your pitches....different arm slot means different pitch...otherwise known as "tipping" your pitches

^^^^what he said.  Used to throw a knucklecurve sidearm, but hitters learned to take it, and wait for my fastball.  So I abandoned it, and now just throw a 2 seam, cutter, and curveball from 3/4.  (I couldn't get any movement on knucklecurve from where I usually threw, and throwing sidearm created a drop effect) 

okay, but will throwing different arm slots like that hurt my arm in future>

IMO, if you have always thrown that way, probably not.  What you might want to consider is learning to throw 2 pitches in each slot if you insist on using multiple slots....just be careful with the slider

Something else, whenever i bring my arm backwards, it like pops out, is this good or bad?

All of your pitches should come from the same slot, always. You need to make the changes asap.

Although lefthookdad may be right, there is a possibility you could hurt yourself later on.

You don't need the knuckleball.   Have you ever heard " a jack of all trades and master of none"?

Have no clue what you mean by last sentence!

Ask yourself this question - do I see guys in MLB on TV throw certain pitches from certain slots?  The answer is no.  You may find a guy who will change slots a couple of times a game but it's just to throw off the hitter but even this is rare.

Pitching is about repeating your mechanics and when you get outside of those mechanics things break down.  As someone said earlier if you only throw "this" pitch out of "that" arm slot then hitters will figure it out and sit on them.  You want to repeat everything to help keep that element of surprise which is what TPM is referring to.

Start finding an arm slot that you can do all your pitches consistently. 

As for the arm popping out.....

A) Does it hurt when you do this?

B) Yes this is a bad thing even if it doesn't hurt.  You're not supposed to feel anything remotely like this.  May want to get this checked out before you go any further.

Good luck

As a hitter, I love when guys tell me what's coming in their deliveries. If you change your arm slot to deliver different pitches, then it's easy for hitters to pick up on what's coming. Also, don't bother with the knuckleball. It's a very difficult pitch to control. You can learn to throw the sinker from the high 3/4 slot; it requires pronation.

TPM hits the nail on the head with "Jack of all trades, master of none." I've known pitchers who knew how to throw 6 or 7 different pitches and threw all of them. Work on controlling the fastball and changeup. Once you master those, work on something that breaks (curve or screwball).

Got a video link at all to find out how to throw a sinker?

Try the internet, you tube has videos.