can't pump gas

[staggerd86c-10]

This might not sound like a bad thing but i can't put gas in my truck, whenever i go to put gas in my truck it kind of spits it back out like a juice box that you blow air into that just leaks everything back out at you. Im not sure what it could be. my switch is on the RH tank and it lets me put gas in that one but im not sure if that would have anything to do with it, this has never happened before and i need to put gas in my truck because my gas guage isnt working. if you guys have a way for me to check my guages let me know the only one that is working is my speedo and its off because of my 3.73s.