When I put gas in my truck it doesn't go straight to the tank.. it back up and takes a min to finally drain so I can pump more..any ideas?

Replace the charcoal canister vent valve.

Take the charcoal canister off and shake it to see if you flooded it with gasoline from topping up the gas tank too far.

Did it always do this?

Please identify your truck.

Tank is not venting properly. Check the vent valve.

Do you have an enemy / someone mad at you? Odds are, there is something in your pipe, leading to the tank.

Make a wire hook to catch and extract the rag somebody stuffed down the filler neck. Maybe you could run a snake camera down the neck to see if it's blocked. A long wire might also indicate the same.

I've owned MANY vehicles in my life, and several did the same thing, even without any blockage, and the only solution was to pump gas slower. ONE, I still own. It's a '63 Ford Falcon. I never put gas in it if I'm in a hurry.

Vent pipe is blocked.

Sounds like it has a venting problem you would have to pull the tank and see where the vent line goes and if somehow it's blocked . I would guess maybe it has something to do with Vapor canister or something like that but you could probably bypass it in some manner you just have to look at it ..