Do fractures always show on Initial xray? Fell & hurt foot 1 wk ago. Doc said no fracture but I'm still in pain and can't walk.

Can miss it. A fracture can be missed if it is not displaced. Re-checking the film after a few days can help as the first step in healing a fracture is some bone resorption and this makes a hairline fracture more apparent.
Foot pain. Stress fractures typically do not show up on xray until 10-14 days after the injury in most patients! You may need a follow up and/or 2nd opinion.