[timgco]

what year?
how many miles?

A couple of things some to mind from your description:
1: rotted body mounts up front and/or swaybar link/ bushing
2: air bag ride height sensor (arms in rear wheelwells) some were adjustable and if one is off from the other it will cause side to side issues as well.
3: bad bag(s)

if you push the ride height button (make sure all doors are closed) measure the distance from the center of your hub to the bottom of the wheel well. Make sure you are on flat ground and measure in the same spot.

4: bad shock can also get your truck upset from L to R
5: 4 wheel alignment? uneven worn tires? psi in tires?


I know it doesn't narrow it down to just one thing, but these are some of the issues that I know of.