Joni Eareckson Tada titled When God Weeps: Why Our Sufferings Matter to the Almighty. The interesting thing is that despite the horrendous suffering she has endured in her life she has clung to and grown in her relationship with God. What is it in the scriptures that she understands that explains why God allows suffering? Looking at her list is a great place to start. Follow the link to see her list.
36 Purposes of God in Our Suffering - Apologetics 315