I have a 03' Pat.. set at 50 lbs.

With my old alpine, it was set at 56 pounds and i drew it with ease. At 50 lbs, Its extremely hard to pull back the bowtech. Is it because of the infinity cam? Is it really harder to draw back than a true 50 # bow?

just wondering cause league tomorrow is gunna rape my arm.... that is if i can get through my 45 shots

That depends on what you are comparing it to. I have no idea which "old alpine" you have or what cam system was on it but it is safe to say that a 50 lb round wheel or soft cam bow will feel much easier to draw than a 50 lb hard drawing single cam like the Infiniti cam. Both are "true 50 pound" bows. The difference is the length of the draw cycle that each bow actually maintains that 50 lb peak weight. The harder a cam is to draw then the longer it maintains the peak weight and the faster it is.