If there is no moral Lawgiver, then there is no way to explain the sense of moral wrong and moral right we all possess. C.S. Lewis said that evil is God's megaphone to a non-believing world. Evil speaks of moral law. A second principle of logic we need to consider is the fact that an apparently evil state of affairs will often bring about an even better state of affairs. The problem is that we often do not recognize this fact until we have the advantage of hindsight.
Physical pain is often highly beneficial as well.
The problem of human evil is rooted in the nature of God and the nature of love and the nature of mankind. I would argue that, above all else, personal beings desire personal relationships with other personal beings. So it makes sense that God, as a personal being, would desire to create us in such a way that He could have a meaningful, personal , and loving relationship with us. But this has a severe price. Let us consider the nature of love and its consequences.