I haven't read any Flash before the New 52, so I just had a quick question:

Does he get tired? Does he need to rest, or does the Speed Force give him the energy to run indefinitely?

That's where the speed force kicks in. When there wasn't a speed force, Wally had to eat large amount of food because of his metabolism and slept for a day or two at times.
BB

yes.

@DanialCarroll: Maaaaaaaaybe because I’ve definitely seen flash bend over breathing for air out of exhaustion but ive also seen him run from the black racer at top speed for a few years without getting tired so I’m not sure.

Depends. Typically he doesn’t. But usually when he says he’s tired theres something going on with the speed force. In current Flash the speed force is dying and so he’s getting tired all the time. When he was the negative flash and tied to the negative speed force it physically hurt him to run. But in normal context, with nothing strange going on with the speed force, he doesn’t get tired