WAS IT SELF- DEFENSE OR NOT?

Bang, the sound of a gun as it ends the life of another one of our youngsters. Every time you turn on the news there is a story about another teen's life ending early. Around 7:25 pm Sunday Evening, February 26, Trayvon Martin joined the statistics of innocent young black men shot and killed at an early age. George Zimmerman, a 28-year-old neighborhood watch captain, shot Martin in self defense, or so he says. Around 7:00 p.m that night Zimmerman called 911 to report "a suspicious person" in his gated community. Zimmerman tells the 911 operator that he is following the teen after he started to run, the dispatcher tells him," we don't need you to do that" but Zimmerman purses Martin anyway, but then he states he lost sight of him. according to phone records around 7:10 Martin was on the phone with his girlfriend when he saw Zimmerman while returning from a convenience store to the home of his father's fiancee. At a News conference on March 20, the Martin family attorney says Martin's girlfriend heard someone ask Martin what he was doing and Martin asking why was the man following him. she then gets the impression that there is an altercation, during which the earpiece falls from martin's ear and the connection goes dead. According to a story later confirmed by the police, Zimmerman tells authorities that after Zimmerman briefly lost track of Martin, the teen approached him, and after the two exchanged words, Zimmerman says he reached for his cellphone , and then martin punches him in the nose. My question is why was Zimmerman reaching for Martin's cellphone, what did the phone have to do with him? After he gets punched Zimmerman claims martin pins him to the ground and begins slamming his head into the sidewalk. I believe Zimmerman is leaving some of the story out because it makes no sense for Martin an innocent teen who was unarmed and minding his own business, to out of the blue pin Zimmerman on the ground and start banging his head on the ground. Another question is why, after he saw that Martin was unarmed, Why did Zimmerman shoot Martin? At the time of his murder Martin was carrying only a small amount of cash, a bag of skittles, and a can of Arizona iced tea. Zimmerman claims that he shot Martin in self-defense. How was it self defense if the teen was unarmed and not dangerous? This is basically a case of right or wrong was it wrong for Zimmerman to assume that, just because Martin was a black male wearing a dark pull over, Martin was armed and dangerous?