my experience with two gm 2500's is that the stock shocks are not valved for heavy towing. A set of bilsteins will HELP. Note I said, help. not eliminate the problem. part of the problem is basic physics in the coupling between the trailer and tow vehicle, especially on frost heaves or bad concrete roads.
To futher reduce the problem an Air Safe Air hitch will make a huge improvement. But it comes with a price (a) $$$, not inexpensive, but does what it claims, and (b) it's heavy hitch, around 100lbs for the Class VI which I have.
It does work well with a WD hitch, no issue there.