To me, it is just you, the brain beginning to realize that the conscious identity you, the brain created for yourself is not real. You, the brain cannot be aware of yourself. So you start to see yourself as immaterial.
The body feels things, like pain and transfers this information to you the central nervous system of your body. This allows you to take action with regard to your environment. You can at least observe your body and what is happening to it and start to wonder who is it that is observing.