"Do you have something for me?"
Translation:Masz coś dla mnie?
You have to add "Nie" before.
Only "Nie masz czegoś dla mnie?" is correct sentence in Polish, but it means something like "Do you not have something for me?" It has same meaning as "Masz coś dla mnie?" but with extra negation which does not change the meaning of the question (asking about something to work on).
"Masz czegoś dla mnie?" will be understood, but no one in Poland will use "czegoś" without "Nie" only "coś".
Good luck in further learning! :)
That is really good to know. But smoke is comming out of my ears, now! 8-)