Answer:
I am an instrument that you can hear but cannot see or touch. What am I?
I am gentle enough to soothe your skin light enough to fly in the sky and strong enough to crack rocks.
I make a loud sound when I'm changing. When I do change I get bigger but weigh less. What am I?
A young man wants to have me but when he has me he no longer wants me. Blade in hand he attacks me and does his best to remove me. Yet he knows that it is all in vain.
You may enter, but you may not come in. I have space, but no room, I have keys, but open no lock. What am I?
The answer I give is yes, but what I mean is no. What was the question?