"Are you frying something?"
Well, if you ask "Smażysz coś?", that's only two words so the pronoun 'coś' has no other option but to land at the end of the sentence. But if you use Formal You, that's already three words and you can avoid putting 'coś' at the end. And "[Czy/] pan coś smaży?" is already accepted.
And where's the subject? You can't omit the Formal You pronoun, because then you arrive at "Does [he/she] fry something?"
I believe that you can do this in Spanish (not sure) but Spanish generally can be very ambigous sometimes... just see how many meanings "su gato" can have ;)