Suffering is a fascinating topic with many diverse explanations. Gnostics believe that suffering is an unfortunate part of a malicious world created by a demiurge. Buddhist believe that all life is suffering and that suffering is caused by attachment. Christians state that suffering originates from original sin. Some New Agers believe that life is a school and suffering is here to teach us a lesson.
I do not know which philosophy is correct. Maybe they are all wrong. What I do know is that suffering is the most effective way to grow. There is no more effective motivator than pain. One grows through adversity. When you are going through the darkest night, this is when your spirit is remodeling itself into something stronger. Suffering hurts badly. Use this pain to transform into something beautiful. Use the pain to make a change.