Some Christians think we need punishment and therefore there must be suffering
Reverend Julie Nicholson lost her daughter in the 7/7 terror bombings. She couldn't forgive the bombers. She believes that the terrorists were acting freely and were totally responsible for what they did.
If there were no suffering, there would be no punishment for terrorists, and therefore no justice. We do need punishing because if we didn't get punished for anything we do then everybody would be bad and get away with it where as punishment stops a lot of bad hapening. We need punishment because otherwise we could do anything we wanted even though it could make the world worse or make people unhappy. If someone killed some one and nothing happened about it then everytime you didn't like someone you could just kill them so we do need punishment.
Some very faithful christians would believe that this is the best of all possible worlds and that suffering is necessary for the existence of humanity. For example if a murder took place than the murderer would deserve punishment.
Punishment is a consequence of people's wrong decisions. The worse the sin the stronger the punishment. People do need to have some kind of punishment to avoid having to much free will and if we didnt have a punishment we wouldnt really care about the consequences of the things we did wrong because there would be nothing anybody could do about it. When we have too much free will suffering will follow through punishment. However some people do get punished for the wrong reasons which leads to suffering.