Time, and our particular personality thinking patterns, are really tied to this physical body and the Earth/Sun relationship. Every experience I've ever had suggests there really isn't much to be afraid of, especially when you surrender from the body as you do going into OBE's or mystical experiences. Once you let go of the fear of death (of the body), and you enter that non-corporeal state where you realize you are not the body, then what is there to be afraid of? You have just proven that you are immortal in some capacity.
The idea of eternity linked to pain is a human conception. It's when we try to project our humanness onto infinity that it makes us recoil, but you can't get to infinity with the body-mind anyway.. going through the eye of the needles means abandoning the body and all the crap we think is important. And from all accounts of those who've been through it, mystically or NDE, the dropping of the body/mind is pure ecstasy.. it's the clinging that causes the pain.