Just as, when we touch a live wire, the electric force infuses itself into our body, when we deeply meditate on God the power of the whole universe seeks entry into our personality.
The pain generally felt at death is due to the nature of the intensity of the desires with which one continued to live in the physical body. The more is the love for the Universal Being entertained in life, the less would be the pain and agony of departing from the body.
The more one becomes fit for the practice of Advaita Vedanta, the less is the consciousness of the body and world around. Advaita and body-consciousness do not go together.