Best SHOES for standing all day?

So I'm 21 yrs old 120pounds and I work 10hour shifts as a waitress and my legs hurt so badly!! Its not even my feet that hurt, I bought these flat shoes that are comfortable, but I'm guessing its not doing its job support wise. My legs hurt really bad all the time and of course I'm not allowed to sit down. My bones hurt and I get really frustrated making work worse for me. BEST SHOES?