Trancework tends to open up our subconscious/higher self more so naturally by allowing us to experience very real but fantastic experiences we would never normally experience.
On my first journey many many years ago, a woman led me to a well in the ground, when I looked down into it, I fell in. I passed out physically and when I woke up, I felt differently. People all have different experiences, but each one has the same general meaning. We become closer to the spiritual and our higher selves as doors open for us. Trance is an excellent tool to tap into our spirit by fully letting go of the physical.
Hearing voices is clairaudiency. If I was possessed everytime I heard a spirit speak to me, I'd be a drive thru! You're not possessed and nothing is in you. The experienced allowed you to tap into apart of yourself that laid dormant. It awakened and now your mind is open to what was always there.
I would definitely keep up your relationship with Isis and Osiris. You're doing great. It is through my belief and own experience, that such high beings send messengers to act as them in their place or send a small fragment of their consciousness/energy to you. If you sense their presence, they are watching over you. If you hear them whispering to you, they are guiding you. Most spirits don't like to talk outloud, they have no need for it. They merely need to think of you and project the idea to your mind and you will pick it up and interpret the message in your own language, through emotions not of your own, or in images that your mind interprets that would best convey the message.