In each phase of the faith cycle, pain serves as an obstacle to progress. It hurts to change your desires. It is unpleasant to realize your desires are inclined towards something less than what you thought. It is painful to uproot a deep-seated desire.
It hurts to exercise reason. It is unpleasant to overcome irrational emotion. It can be painful to fight misplaced desire with logic. It takes effort to learn and to recognize and fight against mental biases.
It hurts to act towards the outcomes we seek. Effort is never easy, and things of greater worth almost always require not just more effort, but much greater effort. Action almost always reveals that the path is much harder than you expected. It hurts to realize that what you seek will require far greater effort, far greater sacrifice, and much more time than you thought.
Without faith, the inevitable pain present in each step of the faith cycle will waylay you. With faith, you can conquer the obstacles of discomfort and toil that lie between your present circumstances and the outcomes you seek.