....

What happened that got you fired, if I may ask?

something about lack of productivity. not being fast enough for what they needed.. they wanted 3 pallets of stock done a day when i was only doing 1.. though i was being asked to people greet every single day for 2-3 hours a day.. how the hell am i supposed to get anything done when they ask me to do that

Your suppose to tell them your job comes first. It's a sad part of the way the corp work's, but that's how it's done. Sometimes you just have to outright tell the manager/team lead/Supervisor, that you can't do another job atm. It seem's wrong to say that to a manager, but you were hired to do that job first, not door greet. Maybe Wal-Mart is a lot different that Sam's Club, but I will have been working for Sam's Club for 4 year's once August 2nd comes.

Good luck in finding another job.