Why am I always have dreams of ghosts and speaking with them?

I don't watch ghost shows, I rarely read about it, but I don't know why I keep having ghosts of talking to the dead. Specifically I keep having one about my deceased grandmother. I wake up with my pulse racing but I'm calm throughout the dream, but I'm always deciphering what these ghosts want. I can't ever see them in physical form, but there are signs there are there (smokey haze...it's hard to explain but I always know they are there trying to contact me). This is driving me absolutely nuts, why can't I have a normal night of sleep. And is there any way to try and make these not happen...like I looked up lucid dreaming and so forth, which could possibly help, but any other opinions?