No problem 'finding' a bow, riverknight. I've got 'em already. I've even been known to make my own longbows.
Tim, I think it's a combination of things. Mainly the actual weight of the compound vs the actual weight of my recurves and longbows and how much longer I have to hold the compound up vs my stickbows. Maybe even the difference the draw cycle and stored energy.
My compound stores a good 40% more energy than the recurves and longbows do. That means I'm putting 40% more energy into drawing the compound, and probably putting 40% more strain on the shoulder for the same draw weight.
A trad bow hits peak weight for you at your draw length. My style of shooting is I aim while I'm drawing, when I hit my anchor everything should be lined up (SHOULD be lined up... I miss sometimes[&o]), so there's often not even a hint of hesitation before the shot is gone. So, I'm at peak weight for a mere fraction of a second. With the compound, it takes me a couple of seconds to pull through the peak and control the draw through the letoff. And then the letoff disrupts my barebow aiming method. It takes me a couple more seconds to reacquire my sight picture before I can release the arrow.
But the bottom line is simply the way my shoulder feels after shooting.
Oldguy, I hadn't figured on leaving the board. [&:]