Engine cranks but will not start

So i'm not sure if my problem is electrical or if it's something to do with my fuel system. When I insert the key and turn it to the on position some times I can hear the fuel pump turn on but only on the first time. If I try to open the switch again I can no longer hear the fuel pump. I checked all of my fuses, fuel pressure and everything seems to be fine, but when I try to crank the engine I have no spark in my coils. Spark plugs, wires, the throttle position sensor, those are all new. I also bought a new battery. My truck was working just fine but just pulled up to a gas station to fuel up and from there it just didn't want to start no matter what I tried. So please if you can help me out and have an idea of what it could be let me know. I need to get it running again. It is my work truck and I haven't been able to work because of it. Thank you