I believe there are three biblical answers to the question of Why suffering? The first is that we live in a fallen world; the second is that foolish and sinful behavior results in painful consequences.
God allows us to be tempted and tested.
“Beloved, do not be surprised at the fiery trial when it comes upon you to test you, as though something strange were happening to you.” 1 Pet 4:12
God Himself tempts no one, but He can allow the enemy to tempt or test us. Job’s suffering was a result of testing. Abraham’s obedience was tested when God asked Him to sacrifice Isaac. Jesus was tempted by the devil, and we are tempted when we are lured and enticed by our own desires.
Temptation reveals our hidden desires, and shows us what we long for more than the Lord. We learn what we have placed as gods in our hearts before Him, so that we may repent of our sin and remain faithful to Him who has purchased us with His own blood.