2011 f150 tailgate centre issue

[f150]

hey guys new to the forum I bought a 2011 5.0l crew cab f150 about a month ago and im having issues getting the tailgate to sit center and have even spaces on both sides. I have replaced both strikers so those are new and I installed a new rubber insert that goes over the pivot point on the truck (passenger side) . Im wondering if maybe there is some debris jammed in where the tailgate swivels on the driver side?? not sure. if anyone has any info or advice for me it would be much appreciated. Thanks Dylan