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: 500 is at my end and my start, yet 5 is at my heart.
The first letter and the first number make me complete.
My name is that of a king.

What am I?

Question: A smooth dance, a ball sport, a place to stay, an Asian country, and a girl's name.

What's her name?

Question: I'm teary-eyed but never cry.
Silver-tongued, but never lie.
Double-winged, but never fly.
Air-cooled, but never dry.

What am I?

Question: I can run but never walk. Wherever I go, thought are close behind me.

What am I?