Pain and suffering are consequences of the fall. If you read through the account of the fall in Genesis, God tells Adam and Eve that life will be much harder for them from that point on. Let's think about the fall theologically for a moment. What exactly was it that Adam and Eve did? They ate of the fruit from the one tree that God expressly told them not to eat of. The fall is really about making choices that are contrary to God's will.
Because the only perfect will is God's, every choice that we make outside of God's will is flawed. God had a choice in creating us. He could have made us as wind-up toys that do exactly what he says, or he could make us creatures with a free will. He chose the latter of these two options. It is easy to get a wind-up toy to love you, but is this really love? God created each one of us hoping that we would turn to him in love and live in accordance with his will.
Think about an orchestra for a moment. Even the best symphony in the world would sound terrible without a conductor and without sheet music. Each person would play whatever note they want in whatever tempo they want. Now imagine the same orchestra with conductor and music...it would sound quite beautiful. I think it is the same thing between God and us. When we are making choices according to our own wills, everyone runs in different directions with different agendas. We end up with pain and suffering because each one of us is trying coerce everyone else into our agendas. We are trying to conduct God's symphony for him.
This is why Jesus came into the world. We needed some outside help to redeem us and to redeem the creation. As more and more people sign on to Jesus' agenda, the world will begin to look like a better place. Of course none of this will be perfect because we are still fallen creatures. Every once in awhile, however, we can get little glimpses of what that might be like.
In the book of Revelation the Apostle John writes that there will be a new heaven and a new earth. He also says that at that time, "He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning nor crying nor pain anymore, for the former things have passed away.Â” (Rev. 21:4) This is what it was like in the Garden of Eden before the fall, and this is what it will be like in the new heaven and new earth after God's creation has been fully redeemed.
In the mean time, we live in the midst of pain and suffering. This is our problem because we are sinful creatures. Our God keeps calling us back to him, but we are still creatures with free-wills and it is our burden to respond. Some of us do respond and we are allowed to work on God's team as change agents, helping him to redeem the world. Those of us who hear the Gospel are the wheat, but there are still a lot of weeds growing alongside us (Mt. 13:24-30, 36-43). This is why there is still pain and suffering in the world. It is not something God desires. I am sure he sheds tears every day over the pain and sorrow that we cause one another. But until he comes again in power and glory, there will still be multiple agendas causing discord instead of the harmony that God intended.