Humans are generally good at doing whats in their best interest in the short tmer, but bad at planning for the long term (1 marshmallow now vs 2 later). This inability to plan for long term is often the cause for pain. Examples:
Easy to eat sugar that will make you feel good now, but you’ll feel bad later
Easy to go for a short term dopamine hit, hard to deal with root problems
Coordination is the best tools humans have to be prosperous. Among other factors, to coordinate effectively people need to have a long time horizon. But because humans are bad at thinking long term, we often fail and cause ourselves pain (moloch). Examples:
We’d all be better off with free trade but instead put tariffs on each other
We’d all be better off without war but often fight each other
Thus most pain, whether at an individual or societal level is a result of humans being bad at thinking long term. Which is understandable - we evolved from animals, and thus succumb to our animal instincts. But if we want to be better people and live in a better society, we need to defer present benefit for future benefit.