Yes....
No.
The reason why most people die when shot in the head is because the bullet hit a major artery or some vital part of the brain, I might be wrong about which causes the death or if it's just one and not the other.
CoD is not realistic, because getting shot in the head doesn't instantly kill you, getting shot in the legs would make you fall down and cry in pain about the fact that you just got shot in the legs, getting shot in the chest would probably cause you to stop and wince, and possibly fall because you just got shot.
Hell, some people who got shot in the head don't even realize it. I once saw a video about this one guy who got shot in the head by a stray bullet, didn't even realize it was a bullet. He just shrugged it off as some brick that fell on him or something. But he didn't even realize he actually got shot in the head until he went to the doctor for the chronic head-aches he had afterwards.
AND HE LIVED.