[harshreality]

Emotional pain is critical for empathy. Unless you believe in the purely rational theory of human behavior, people have to feel what will be emotionally painful for others before acting in a way that minimizes emotional pain.

Physical pain is also important. It keeps you from doing stupid things that end up with you getting hurt.

Both mental and physical pain can be modulated/reduced somewhat through psychological training (one form of which would be meditation). I think making pain reduction any easier could cause more problems than it solves.