yes this quite common and most people would experience this. It is usally in the form of being touched some where like the back of your shoulder or top of you head, and the feeling that someone is behind you, when there isn't.
This does not mean a ghost though, as everyone has what is called spirit guides. These are spirits that stay with us through out our lives, trying to give us some guidance during life. So most of the time it is them just letting you know that they are there, and they do that by entering your aura, which causes these feelings you get.
But check it out anyway, cause you never no. You investigate cemertaries so it is quite easy to pick up a stray spirit that is just lingering around.
Mystical Magic