Answer:
Always in you, sometimes on you. If I surround you, I can kill you. What am I?
I spend the day at the window, go to the table for meals, and hide at night. What am I?
Break me and I am better, immediately set and harder to be broken again. What am I?
lighter than feather and softer than silk yet the strongest man in the world cannot hold me for more than a few minutes.
I only exist when you are here. Where you never were I can never be.
The answer I give is yes, but what I mean is no. What was the question?