The word going can have different meanings. Two of them are as a synonym for walking, e.g. "I'm going to the mall", and in the idiom "how's it going" as a synonym for "How are you?". I've noticed that both uses are also valid in french ("Je va a la supermarche", "ca va?") and german ("Ich gehe zum Supermarkt", "Wie geht es dir?"). Is there an explanation why? The usage of "How's it going" as a synonym for "How are you" doesn't seem very natural to me, so I'm curious why it's used in 3 (and probably more) more or less independent languages
I assume that the use of the verb "go" for this kidn of expression doesn't mainly have to do with an actual semantic assocition but simply because "to go" is such an extremely frequent word that has such a large range of usage in complex terms, idioms or even grammatical constructions ("I am going to..." vs. "Je vais...") that the fact that it is used for expressing well-being is simply due to the verb itself being as general and frequent as the question itself.
Which doesn't exclude the possibility of course that the choice of the verb might have developed at an early stage where the languages involved were closer to each other or, due to massive cultural exchange, the usage in one language has jumped over to the others.
But I don't think that a verb like "go" is such an unlikely choice for an expression that often used.
Not exactly true for Russian; we never say “Kak idet?" (How is it going?) but rather "Kak idut dela?" (How are the things going?). "Kak idet?" sounds pretty weird and unnatural to me. Well, I suppose, this is because you imply, when asking the question, that things are actually moving in some direction, changing in time. That is also true for Belarusian. What's even more interesting, in Polish we ask "Jak leci?", which literally means "How is it FLYING?" :)