I heard voices before when I lived in la about 5 miles from probably one of the biggest cemeteries out there. It was really weird, I'm not crazy at all, I think these were ghosts. It sounded like 1000 people talking all at once, but I could single out a few voices at a time if I wanted and hear their messages for me. After I moved from that particular house, all voices ceased. I also heard birds chirping, and rain. I think there is just a parallel universe right here, all around us, that's all we're getting quantum interference from the other side every once in a while. I would try camping or staying in a different place and see if these voices still follow you.