I Apparently Have A Pipe Leak Inside My Wall Behind The Toilet. I Have Turned Water Valve Off And Emptied Tank And Bowl But The Bowl Continually Fills Back Up. Where Is This Water Coming From And What Causes This?

Since there is only one point of connection for a water source to your toilet, the valve can be your only faulty item. A leaky pipe in the wall would have the opposite effect, you would be less likely to have water flowing to the toilet.
I would recommend shutting off water at the meter, open a faucet to releive pressure in the line, remove the valve and replace with new.