When you try to spin, do you have any idea what gear you're using? Pay attention next time you're out and post it here. I wonder if you're trying to spin in too big of a gear for where you are in terms of aerobic capacity and leg strength.

That said, not all of us are spinners. I can comfortably spin at a high cadence, but I'm often on the lower end of what's often touted as "ideal," so I border on being a masher.