You simply shut it down and then no start? you didn't do any work on the truck?
First thing I would check is the "fuel system" relay in the under hood fuse box located behind the driver side battery. I have had issues with the electrical connections on that relay with my truck.
Second would be to check the injection pump wiring harness connection, make sure its pushed all the way on and tight(harness is on back side injection pump, closest to the fire wall).
If all that fails crack open a couple of injector lines and turn over the engine and check for fuel flow.
You may also have a bad lift pump that has just started to show.
If none of this stuff works post back and ill continue with diagnostics
CJ