You have numerous problems with your setup. I would take the whole thing apart and start over.
There should be a pin/bolt sticking out of the hitch head pointing back toward the shank. It is there to put washers on that adjust the tilt of the hitch head. Put enough washers on there (usually up to 8) to get the bars pointed down towards the ground before you raise them up with the chains. This amount of tilt is adjustable via those washers. The amount of tilt is used to determine the level of the bars and adjust the amount of tension placed on them when the chains are drawn up.
The number of chain links under tension (between the bars and the snap-up brackets) must be a minimum of 5 to allow for movement back and forth while turning. In most cases, with the size of your A frame you should have 6 or more. At the present time you only have 4. Those bars should be parallel to the A frame when the chains are drawn up. You adjust the tilt of the hitch head (via those washers) until you get that correct along with the amount of weight distribution you need.
Under the ball mount platform on the other side of the hitch (the side facing the trailer) is a small bolt that needs to be tightened up to jam the hitch head in place against those washers. This bolt will loosen up frequently and needs to be checked before each trip.
Doing the above will then allow you to tighten the large top and bottom bolts holding the hitch head on the shank without the head trying to twist out of adjustment.
Now that you have the angle adjusted, you need to determine where on the shank you have the hitch head mounted. This is the adjustment that you use to level the trailer. Once you have that height adjustment done you can torque those large bolts down to the right amount (usually 400-450ft/lbs.) That is a very large amount so the large crescent wrench in your toolbox probably is not going to do the job!
We have a
very good tutorial here that will help you get your hitch set up correctly. Follow those directions, especially the first parts, and you should be good to go.
Good luck and I hope this helps you a bit.:)
Barney