Feenixx,
you call it craving, and so i;'m not sure if it's what i might call hunger and others might call void or lack.
if you don't know what it's FOR, that's fine. but imo it's important not to deny that there's a perceived need. whether it's "real" or not remains to be seen
i was sober quite a while before i got restless for 'something'. not a substance. that, i knew.
it was an uncomfortable place for me, and i stayed there for quite a while.