Well, I came upon someone's thoughts on this question online today. I will let you read them and then make a few comments. (This man is a Christian theologian, from what I gather, posting on a forum.)
"Gen. 3:5 states that God knows Good and Evil. Knowing Evil, being aware of it, is not an Evil thing within itself, nor is being aware of Evil some kind of mental sin. Evil is nobody's thoughts, ours or Gods, God just knows it would eventually be thought of. So he created us to deal with these thoughts first, by rubbing our faces in it, we will retain a permanent attitude toward it throughout eternity, permanently convinced it is just no Good. I believe we will be able to understand what Evil is, and through becoming like God, it can never penetrate us again. God holds the power to block anything from his creations' minds, but he did not choose to do this with Evil. It then is part of our creation, our education, our very birth. I think this whole experience with Evil is not only for humanity, but the entire heavenly host of created beings are learning from this that we go through. One of the reasons Heaven will rejoice at our coronation is because they will be happy for us that the Great Suffering is over, they who have never suffered before. Never felt pain or misery. Never been slaves to Evil."
Well, I don't know if everything he said there is 100% true, but I do think he has a good point. It makes me think:
1. That our freedom in Christ is celebrated by all of Heaven and sweet to us because we know the pain of slavery to sin and the effects of the Evil sin brings into our lives.
2. That all of this (life, history, pain and suffering) are designed to make us and everyone else (heavenly beings) positively sure that Evil is bad and God is good.
3. The writer makes it sound like God intended us as an object lesson in good vs evil, when I've always thought He intended a perfect world when He created it and we messed it up. I think he's wrong.
The answer to why is there evil in the world is simple, right? --because there's sin in the world. But Satan tempted Eve- he was already in the world before sin. So why were we put in the same place as Satan to begin with? And did Eve's act of sin give him the power to be Evil on Earth? Does our personal sin give him power to be Evil in our lives and cause us suffering? What about Job? He was blameless and yet experienced tremendous suffering! So our pain and suffering are not dependent on our sin or lack thereof (although sin causes death). It is dependent on God giving Satan permission to do us harm, which God then uses to bring about good in our lives (since he only intends good for us and not evil). So to God, pain and suffering must not equal Evil. And Evil does not equal sin, since it existed before the Fall.
So maybe we are an object lesson after all. Or maybe this is going to take more thought and questioning. Or maybe it's too complicated and I need not even try to understand this side of heaven.