I've been asked hundreds of times why God allows evil to take place, and I have to tell you honestly that I do not know the answer not fully. The Bible talks about "the mystery of iniquity" (2 Thessalonians 2:7, KJV) and that's what evil is: a mystery.
But let me tell you three very important truths about evil that might help you. First, the Bible tells us that evil does not come from God, nor can we blame God for all the evils in the world. Evil comes instead from Satan, and it entered this world when Satan deceived Adam and Eve and caused them to turn against God. Both evil and Satan are real, and the two go hand-in-hand.
Second, the Bible tells us that someday all evil will be banished. The vast spiritual conflict between Satan and God that has raged from the beginning of time will be over, and God will be triumphant. Someday all evil will be cast "into everlasting fire, prepared for the devil and his angels" (Matthew 25:41, KJV).
Third, the Bible tells us that in the meantime, God can give us victory over evil. This doesn't mean bad things will never happen to us but even when they do, we can know God is with us, and He will give us strength to stand against them. Isn't it better to face life's problems with God rather than without Him? No, we may not understand everything that happens to us but when we know Christ, we know we are on the winning side. Why not commit your life to Him today?