Testimony is only valid to the person who had the experience. Surya, if you are brave enough to take one of those philosophy classes I apparently could not survive in, try Philosophy of Religion. This was covered prominently. If you have some mystical experience, that may validate it for you, but you cannot use your experience to show that mysticism is objectively true. Mystical experiences are induced by the brain to the best of our knowledge. So, your experience is no more or less valid that the guy on LSD who gets attacked by the troll. Are you willing to accept his testimony that trolls truly exist? (Well, you may, but most would not).
As for consciousness being from the brain, there is no reason to believe it is not. We do not know either way, but if all the rest of human experience is in the brain (love, pain, happiness, sadness, addiction, etc etc etc) why should we believe consciousness (which relies on these) is free of the brain? The answer; we shouldn't.