Why does evil and suffering cause problems for religious believers?

Sin or evil exist in our world today and affects everyone regardless of whether they are "good" or "bad" because God still allows individuals their free will. The assumption is that somehow God permits (as in some way to agree with) or condones the evil that is being perpetrated. In fact, God grieves and stands ready to intervene in the life of the victim as well as the perpetrator. He even promises to take the situation and eventually work something good (if man is willing) out of such things. 

Yes, God is omniscient and knows what will take place. There are countless testimonies of individuals who believe God to have intervened and prevented evil. But God is not obligated, especially to those who have little interest, or belief in Him. 

God is also omnipotent and as such is more powerful than evil. Just because God does not overpower evil or stop something from happening only means for reasons known to Himself He chooses to restrain His power. This happens day in and day out in the natural world. The stronger, wiser one with more ability shows restraint giving the appearance of impotency or weakness. 

If in fact God went against His desire for man to have free will and chose to intervene in the evil that exists at what point should He stop? Would God be free to stop major catastrophes and mass genocide but only that evil. What about the evil of theft of anothers possessions, or impure thoughts or lying? Does God now have permission to address those forms of evil as well? Some might say yes, but many more would cry foul. Their claim would be they have free will to live as they please. Thus bringing us back to the very beginning of the discussion. 

It has been, and always will be that man walks with God as He intended from the beginning. In harmonious submission to His ways. For those who find reconciliation back to God, this process has already begun.