Dave's suggestion should work fine...
An alternative, if you've got somebody helping you, is to use the trailer brakes instead of wheel chocks. Use your brake controller to manually engage the trailer brakes on full, and let your tow vehicle pull forward against the trailer brakes. Have your helper engage the latch while you hold the trailer brakes on. No strength needed.
Once I figured out that the ball has to be forward in the hitch before the latch can be engaged or released, most of my hitching problems went away. As others have commented, the hitch some times holds onto the ball even with the latch released and so starts to lift the tow vehicle as the trailer tongue is raised. The solution for me is to bounce on the bumper once or twice.
2013 Escape 19 ("The Dog House") , 2012 Nissan Frontier