definitely some interesting theories..
but like benzyme said, pain is necessary for survival, otherwise you would never learn to avoid something that can cause you pain,
Individuals with a rare condition who cannot feel any physical pain known as congenital analgesia usually don't live very long, usually due to simple mistakes or accidents.
Mr pearce speaks about psychological pain, but I believe its there for the same reason as physical pain, its just evolutionary.
your best bet is to learn to enjoy the pain
Expect nothing, Receive everything.
"Experiment and extrapolation is the only means the organic chemists (humans) currrently have - in contrast to "God" (and possibly R. B. Woodward). "
He alone sees truly who sees the Absolute the same in every creature...seeing the same Absolute everywhere, he does not harm himself or others. - The Bhagavad Gita
"The most beautiful thing we can experience, is the mysterious. The source of all true art and science."