There is so much suffering in this world because of our sins. We are suffering because of our injustice. There is so much sin in the world. There is disobedience. There is injustice. There is so much evil in this world. Since justice must be served in everywhere possible, that is why there is much suffering. We are suffering because of our sins and disobedience.
When God created the world at the beginning, it was a perfect world. There was no evil in it. Everything that God created was very perfect. We should have enjoyed a happy life. But then sin came in. Man disobeyed God's commandments. He ate of the forbidden fruit. So, that act of disobedience, sin came into the world.
Sin manifested in the world in many ways. Evil rules in virtually everything that we do. Man devices different ways of disobeying God’s commandments. There is so much sin in the world. There is so much evil in the world.
Why there is much suffering in this world is because every sinful act must be payed for. There is so much suffering because we are sinned and disobeyed God's commandments.