Is or was there a philosophy which examines a hypothesis that in fact nothing "exists" except maybe questions?
I know there are philosophies that state that reality is a simulation etc. but I mean that not even a simulation exists. The only "things" that exist are the questions we ask.

Is there a philosophy which [argues that] nothing exists?. There are two mutually exclusive meanings to it: Do you mean the thesis that non-existence exists in some sense, e.g. that nonexistent (fictional) objects exist or, to the contrary that, with Parmenides, what is not, cannot exist? (I'd think you mean the latter, but you could reassure us.) – DBK Oct 29 '12 at 12:27