I think I may have figured out my own problem and would like to know if this would make sense.

When I tried to start it again this evening, I got one smooth crank out of it but then it tightened up again. So I took the engine out again and and noticed that it unscrewed a bit and tightened right up against the clutch bell making it impossible to turn it over with the starter.

I forgot to buy a piston locking tool to make everything as tight as it can be. So I think that this is the problem why it's making it impossible to turn over.

Does this make sense and has anyone ran into this kind of problem before?