Skeptics often ask, if there is a God and God is Love, why does He allow such evil and suffering to go on in the world?  The short answer is free will.  God did not want robots, if he did he would have created them.  Instead he created man in His image and gave him a brain and the ability to make his own choices.

He parked Adam and Eve in a beautiful garden with everything they would ever need and all they had to do was enjoy it and follow one rule.  He told them they could eat any of the beautiful fruit from any of the trees, except one. ( Genesis 2:17 )  And what did they do?  They ate from that tree -- The tree of the knowledge of good and evil (Gen 3:6 .)  That was the first of many, many sins that would be committed by man.  Once sin was let into the world through Adam (Romans 5 ) it infected us all, every generation inlcuding ours. 

Suffering exists because sin exists.  When people choose sin over Godliness bad things happen. 

There are other possiblities or angles that we shouldn't ignore either.  For instance, God sometimes uses suffering to teach or discipline us - just like we make our children do things they don't like for their own good (like cleaning their rooms, getting a shot, or eating brussel sprouts.)  On other occassions God may allow something evil to happen for the greater good of His divine plan.  For instance, he sent Jesus into the world knowing He would be killed and used this situation for the benefit of all mankind.

NOTE:  "evil" doesn't necesarily mean killing kittens, trying to take over the world, or anything to that extreme (although those things are evil.) evil is anything against the will of God.