A common question in times of pain is: "Why me?"
Even devoted Christians often struggle with the great question "Why does God allow suffering?"
The answer is not really long and complicated. It doesn't take a university degree to understand, but few people are willing to accept the simplicity of the truth. As the Bible says: "the wisdom of God is foolishness to man." And yet, the 'foolishness' of God is far beyond the wisdom of man. What it does take is the Spirit of God to understand the things of God.
Suffering comes down to a result of choice. God gave man freedom of choice. When we make bad choices, suffering and pain is the result. Not always directly, and not always immediately, but eventually there is no escape from the consequences of our decisions. God allows the pain, not to be cruel, but to convince us that His Way is The Right Way.
Right now, it seems senseless that children, especially, suffer horribly, but it can all be traced back to the choices of humanity. Most especially our choice to tell God we don't need Him and we don't want Him.
God won't force us to do things His way, but nor will He rescue us from our failed paradise.
We can be excited and encouraged to know that God's plan is for everyone, and that He has ordained a second resurrection (raising the dead) to ensure that every man, woman and child has the opportunity to know Him and choose the Life He has to offer.
Beyond that time, God's promise for eternity is that there will be "...no more death, nor sorrow, nor crying. There shall be no more pain..." (Revelation 21:4)
For now, pain is a by-product of human choice - we must suffer because we (humanity) choose our way. We can look forward to Christ's return, when we will learn to do things God's way and suffering will come to an end.
For a more detailed explanation of human suffering, you can read Why Does God Allow Suffering, or to learn more about God's plan for all of humanity (God has not forgotten or abandoned the millions of dead who never heard the name of Jesus Christ), try reading What Happens After Death.