You see the so-called problem of evil is a much bigger problem (insurmountable) when one's theology attributes to God a concept of sovereignty that makes no genuine room for the exercise of creaturely free-will. Or a concept of God that believes everything that comes to pass is somehow part of his "unconquerable will" (to quote St. Augustine, the first Christian to EVER suggest these pagan concepts). If we somehow have to appeal to God's mysterious decrees (or "secret plan" as Calvin put it), looking for a divine reason behind everything, then YES, the problem of evil is a massive problem. It is massive because essentially God Himself is the cause of the problem. To put it plainly, if you dig deep enough, God is the author of evil in the universe of the God of John Calvin and St. Augustine. There's just no other conclusion if you take their theological concepts to their logical conclusions. Not only that, but because they also assert (how I do not know) that God is all-good and loving, they therefore somehow must assert that the existence of evil is somehow an expression of that goodness and love. strange theology indeed.
thankfully, we don't have to find the source of evil in the world as somehow being sovereignly decreed by God. we can instead find the source of the problem in the misuse of the free will of God's creatures. that is what the early Christians did, that is what C.S. Lewis did and other "responsible" modern-day apologists. I say "responsible" because the other concept of God is a gross misrepresentation of the God and Father of our Lord Jesus Christ.
why is there evil in the world? because people (and angels) have chosen it and continue to do so in the exercise of the own free wills. is God's will being done when we choose to disobey His will? absolutely not! Augustine was completely wrong. God's will is being opposed, thwarted and disobeyed millions of times each day. Every unloving act, selfish deed, slanderous word, rape, murder, etc. are all examples of His will NOT being done. But this is the world HE CREATED. A world where free creatures, can exercise their freedom for either good or evil. To stop each act of evil, would be for God to withdraw the gift of that freedom.
As C.S. Lewis so profoundly puts it, "God willed the free will of men and angels in spite of His knowledge that it could lead in some cases to sin and thence to suffering: i.e., He thought freedom worth creating even at that price."
In other words, the ONLY possible universe where love could be possible is one in which real choices can be made. It was worth the risk for God to create that world. One day He will put a stop to evil and suffering; they are only a temporal realities, not eternal ones for His children.
In other words, God had nothing to do with evil's entrance into the world. And He has nothing to do with it when it happens each and every day. However, He is so good, that He works to bring beauty out of suffering and pain. He is in fact so good at bringing good things out of suffering (which is a testimony to His unfathomable love and heart of redemption) that people 'mistakenly' think that somehow He must have been behind the evil in the first place. No, it wasn't being "allowed for a purpose" as the softer, modern-day version of Calvinism would have it. Evil is evil. Darkness is darkness. And "God is light in whom there is NO DARKNESS AT ALL".
So, there is a satisfying answer to the age-old problem of evil. That is, if you have the Biblical (non-Augustinian/Calvinistic) understanding of the God of love and why He created free creatures in the first place.