Khalid bin Ali bin Mohd Alnbry says:
Back of the head or neck during sleep, may be interpreted with respect to the past and the search for past events.
Text from the site of dream interpretation
Leila tells you about:
If you're sleeping behind a woman, the important news is the meat. If you are sleeping behind a man, in the sense that you have caught. If behind a kid, you indicate that you stay safe from their enemies.
Text from the site of dream interpretation