Yami - He is not back from after death life but it is in the nature of things that dead people are alive and appear in our dreams. The shock is shown in many dreams, and probably occurs because you have not any belief that this can happen.
At the time of the dream you were feeling tired of life - a common feeling when we cannot get enough satisfaction and stimulus. I feel that sometimes one is tired of everything because there are changes you would deeply like to happen, so perhaps you can start making those changes happen. What you wished for, to be taken away from the troubles of living in the body, might come about if you continue to long for death.
Tony