God and Suffering

"The Lord is my rock, and my fortress, and my deliverer; my God, my strength, in whom I will trust; my buckler, and the horn of my salvation, and my high tower" (Psalm 18:2 KJV).

After reading this Bible verse, it appears to me that God protects those who trust in Him. But paradoxically, those that trust in Him sometimes still suffer. It appears that God does not completely protect those who trust in Him from suffering.

Why does God allow those who follow and trust Him to sometimes suffer? Perhaps suffering serves a purpose. Suffering generally changes the direction of a person's life. Without suffering, a person will usually keep on the same course in life. Suffering can change the course.

Given this, perhaps God will sprinkle some suffering into a person's life whenever He wants the person to take on a new direction, such as a job change.