Pleasure And Pain

What's the relationship between pain and pleasure? Is it really like the link between sorrow and joy? Are the two just different sides of a coin? Does one sort of turn into the other from time to time? Or is it possible to have pleasure without pain, ecstasy without agony or happiness without sadness? It may well be. When we are having these experiences, we feel as if we are in a state that we can never get out of. If something hurts now, it can soon stop hurting. Yet if something is good, it need not turn bad.