Try remove the pull start assemble and pull to make sure the starter is work fine. It should be very easy to remove since it is a full crank.

What you discribe is strange. Only time it feel high compression is when you somehow have fuel in the cylinder. But if that is true, the engine is way flooded and you won't be able to start that easily even if you pull slowly first. Besides, assuming it sit upright during storage and fuel would not move up to the cylinder.

Check the starter first.........Or are you getting old??!!........Just kidding!!!

I forgot a simpler test, just take the plug off and pull and see whether it is still tight first, this case, you don't even have to take off 4 screws to remove the starter.