What Am I Riddles

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 have memories, but none of my own,
whatever's on my inside is what is shown.
If I'm ever different it's because you changed me,
I feel like a decoration, here for you to arrange me.

What am I?

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

What am I?