What Am I Riddles

Question: Under pressure is the only way I work,
and by myself is the only way I'm hurt.

What am I?

Question: I dig out tiny caves, and store gold and silver in them. I also build bridges of silver and make crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs my help, yet many people are afraid to let me help them. Who am I?

Question: I'm in everybody but everybody still wants me.
I won't feed you but I'll feed the tree.

What am I?

Question: What is harder to catch the faster you run?

Question: I'm red, blue, purple and green.
No one can reach me, not even the queen.

What am I?