Is there a Czech sentence that would be translated: Why do you stand? Would that sentence be different than: Proč stojiš?
I would never interpret "Proč stojíš." as regular or repeated standing, some details must be added, like:
Proč vždycky stojíš? Proč v metru stojíš.
The basic meanings would be the same, but the version with "standing" is much more common
I'd say that "Why do you stand" is not much used as a simple question, but instead with some context around it: Why do you stand (with your broken leg) when you could sit? Why do you stand there (like a statue) when you can see I need your help lifting this really heavy box? That sort of thing.