Many people have lost sight of the previous promises of God because of the tragedy and sorrow they see in the world all around them. They say if God is love why does he allow evil to plague his children or they say God doesn't care. He doesn't exist, we even go as far as saying the followers of Christ should not suffer or get sick. The truth is believers do get sick, Christ redemption on the cross does not mean we will not suffer or fall prey to evil but it equips us to face suffering because in our suffering believers have hope because we know that suffering is brief and our blessings in heaven are eternal.
Also as believers, we fail to understand that by allowing evil, God is teaching mankind to hate the painful results of sin and learn to love him and his righteousness. NOTE: We suffer because of the fallen world caused by Adam and Eve. Suffering has never been part of God's plan for man and that's why at the beginning (before man disobeyed God) man knew nothing about suffering. He made everything man wanted available for me without any stress. But Adam's disobedience is what brought suffering to mankind. In essence, suffering brought to mankind as a punishment for the sin of disobedience committed by man.
Also, in the life of a Christian, suffering serves some purposes. Just like the son of man suffered, God at times uses suffering as a test for man's faith in him. However, this type of suffering doesn't last long and often comes with rewards at the end. Just like in the case of Job, God allowed Job to suffer in order to know how much faith Job has in him. Job was rewarded in thousands of folds after he passed God's test.
In some cases, we suffer as a result of what we have done in one way or the other. In this scenario, man is considered as the architect of his suffering. Even the law of nature makes us understand that we often reap what we sow. If one sows wickedness, then wickedness he shall get as his reward. Sometimes we might not be the ones to pay for that but those that come after us.
Christ the son of God suffered so that we could be saved. But been saved solely depends on us, as we are required to believe in him.
For God so loves the world that he gave his only son that whosoever believeth in him should not perish but have eternal life.
Those were the exact promise of God, so those who refuse to believe the son of man should be held accountable for their choice. In this case, suffering is a matter of choice because God has given us the opportunity to make our decision.
In summary, man's suffering in this world can be attributed to so many things. It can be seen as a punishment for what man has done. It can also be seen as a necessary stage in life that ushers in greater rewards. It can also be seen as the choice made by man. In all, it is never God's plan for man to suffer. In fact, God is pained when he sees us suffering.
God loves his people, and the plan he has for us all is of good and not of evil. He even sent his son to die for the sins committed by man — the illustration of how he loves us.