He was on the phone with police, reporting suspicious behavior.
"He’s 14 years old. Why doesn’t he have the right to be frightened and feel threatened that a grown man is following him?"
Not relevant. He could feel frightened or not. So what?
"But does it not cross anyone’s minds that a 14 year old should not be in danger of being shot walking home from the store?"
He wasn't in danger of being shot walking home from the store. He was in danger of being shot when he started beating a man's head into the sidewalk.
"The guy police shot down in Walmart. It’s an open carry state. Is this not troubling to anyone?"
It is. I agree with you about that case. But you have your facts wrong about the Zimmerman case.
"Yeah, you know, Zimmerman should have stayed in the car."
Did Zimmerman deserve to be beat to death for getting out of his car?
Even more than that. Zimmerman did not go for his gun until he felt Trayvon grab for it. Up to that point he was taking the beating, of his head on the concrete, only trying to move himself to the grass.