I'm having trouble unhitching receiver from ball

My last ski boat caused me all sorts of similar problems, especially getting it off the hitch. So much so that I burned up two of my trailer tongue jacks trying to force it off.

What I eventually discovered, was if I would just push the trailer back after I was parked, and before I blocked the wheels, it would take enough pressure off the hitch to easily come free.

You might have a completely different issue, but it would be worth a try.