how to say and use "turn in" in french?

Would you please explain the meaning of "stack up" to me. I guess he donesn't stack up. Because he has so many works to do.(I make the sentence by myself) I stack up so many questions to prepare to ask Jim. I assume the first one it's meaning "ready", and the second its "accumulation"

How can I understand "shake off" Nothing a young guy like me can't shake off .Plus,puting off going to the doctor, would you explain that please?

What is the meaning "De qui parlez-vous " in English?