Clunking noise near passenger door

I've noticed some kind of a noise coming from the passenger side front door area of my 98 Tahoe.

It only seems to happen when the vehicle travels over uneven ground and can be felt when you hold a hand against the A-Pillar.

I've thoroughly checked the body panels in and around that area for loose fasteners and I've checked the door and its hinges... nothing wrong that I can detect. I've also thoroughly gone through the suspension to see if there was anything loose and again, nothing.

Any ideas?

Thanks

check you're upper hinge again, they are know for premature wear.