the reason you are hitting your arm could be because of the draw length but because you pins are on the left side of your peep i would bet that you are gripping the bow with a fist. this would explain the hitting of your arm and if you grip it very tightly and twist your wrist or hand at all it will torque the bow. When you cant the bow it changes some things. buy a sight with a level or install one yourself practice until you keep your bow strait it should help By the way this is how you should hold your bow