Do we need pain?

I googled: our soul needs pain to learn

I found:
http://www.physicsforums.com/archive/index.php/t-45269.html
..Of course we need pain. Pain is great.
Pain is an important part of who you are and how you become. It is the signs that tell us what areas need attention. Both mental and emotional pains are equally important to the pleasures.
...

I do think we need pain, of various sorts, to learn. I conclude that because I believe this "reality" in which we live (the Maya, or the illusory reality), is one that is created, and as such was designed for our experiences. Only the experiences, and the lessons we learn from them and integrate into our beings, have any lasting value. Everything else is temporary, and illusory.

I think some mild to medium-strength Salvia trips have aided me in some of my recent insights and realizations. I can't recommend for or against taking Salvia as an aide to understanding oneself and the universe. I can merely say that I think it's helped me see what, inside me and in the world, isn't "real", and as such I can reprogram my understanding and approach to life by debugging my psyche, and removing some of the illusory notions. However, the actual insights I get are generally very simple, and merely point the way to greater understanding. For example, I once noticed that my bowels felt clogged-up. Okay, it's not such a great topic of discussion, but the point is, I'm often reminded of things I may already know, but wasn't paying attention to, when in the light salvia trance (say, just one leaf, smoked). I also sometimes think I have a different personality; a deeper personality, beneath the mask of the ego.

Anyway, the actual insight that led me to create this post was that pain is needed for contrast. Without evil, how would we recognize good? Without "bad" music, how would we recognize "good" music. The latter example seems like a poor one, since music tastes vary so greatly, but perhaps the two are more similar than they at first seem; do not also judgements of what is "evil" and what is "good" vary widely from one belief-system or religion to the next?

Mind you, it isn't a salvia insight. Nor is it a very "deep" insight. Perhaps I should just call it a guess, or a conclusion I arrived at through observation and recalling reading something like that before.