What is perhaps the most frequent challenge raised by atheists and one of the most perplexing questions that troubles many Christians, is the problem of pain and suffering. What is often overlooked is that it is not only a question that Christians must answer, but because it is a thunderstrike at the very core of man's existence, it is a troubling issue that we ALL must face. Before a person thinks his faith shipwrecked, he or she should consider the alternatives, which are less than satisfying if I do say so myself.
According to atheism/naturalism/materialism, pain and suffering have no purpose or redeeming quality, they are just meaningless brute facts of nature. Typical response is to attain relief, although there is no foundation for such assumed human dignity. As there is no life-after, the meaninglessness in suffering is multiplied at death. There remains no hope for the clinically ill, death is final and absolute; after all, man is a mere animal.
Pantheism/reincarnation: Pain and suffering are things that we must accept as the natural cycles of life. They are the ultimate result of one's karma. Any attempt to alleviate the situation could jeopardize a person's future by prolonging the suffering in the person's next life cycle.
Buddhism/Christian Science: Suffering is an illusion. According to Buddhism, to end this suffering, we must cease all desire. For the Christian Scientist, we must attain Christ Consciousness.
Judeo/Christian: Suffering is the result of sin, the fall of creation and thereby, an abnormality. Man also forfeited his authority over the world to Lucifer. Jesus gave the mandate to nurse and care for those who are suffering, as an expression of love toward our neighbor. Being created in His image, it is a matter of human dignity. At the cross, Jesus partook of all our pain and suffering, offering redemption in the midst of our hopelessness and despair. In the end, when God's kingdom is fully manifested, for those who have placed their faith in Christ, suffering will be no more .
Incidentally, I have come to believe that pain serves very important functions that are unique to suffering, which may not necessarily be the result of the fall; but according to The Bible, it does appear to be absent in the new world to come. For more on the subject, I recommend Paul Brand and Phillip Yancey's The Gift of Pain.