This question wells up from the heart when we observe the hurting around us, and when we feel the hurt within us. To the person who is in the midst of suffering, no answer seems fully satisfying, and I certainly don’t pretend to have a complete answer here. But I will make a couple of comments.

In the first place, we need to understand that all pain is the result of sin in this world.

Sin is that which breaks our relationship with God, and brings destruction and death into the world. Note that I said, “All pain is the result of sin in this world".

It’s not necessarily the result of personal sin in the life of the sufferer. Disease, natural disasters, birth defects, and countless other causes of pain, may result from either personal sin, or the evil in this world generally.

We often feel pain for things over which we have had no control.
Let me also say here that my knowing the reason for pain, and God having a reason for pain are two different things. God’s purpose for allowing pain in my life is not dependent upon my knowing what it is.

Having said that, we can note that there are a number of ways in which God uses pain and suffering for a greater good. 1) Sometimes God uses pain or evil to warn us against a greater pain or evil.

As a child, I remember various dogs on the farm getting run over on the road. Even though that saddened me, it also reminded me to be careful when crossing a road. Pain may keep us from self-destruction. In his insightful book The Gift Nobody Wants, Dr. Paul Brand gives numerous examples of how pain protects us from doing things to ourselves that would be self-destructive. His years working with leprosy patients taught him the horrors of a life without pain. The destruction of a limb occurs quickly when a person loses the sensation of pain, which serves to protect it from harmful activity. 2) Pain can produce within us good character virtues. We may gain patience, sensitivity, compassion, and many other terrific traits by undergoing pain.
One who has experienced a certain type of suffering, is often well-equipped to comfort others who experience it. 3) Pain gets our attention, and often causes us to look to God in our helpless state.
English author C.S. Lewis put it well when he noted, “God whispers to us in our pleasures, speaks in our conscience, but shouts in our pains: it is His megaphone to rouse a deaf world."

Are you suffering now in some way? Let me encourage you to turn to Him who created you and sent His Son to die for you. He has not forgotten you, and is with you in your pain. For all who trust and follow the Savior, the pain of this life is only temporary, and He will one day bring them into His presence where “there shall no longer be any mourning, or crying, or pain…" (Rev. 21:4)

Source: http://catholicsay.com/why-does-god-allow-so-much-pain-and-suffering