When Adam fell, creation fell. We live in an imperfect world full of imperfect people.
Sometimes when things go wrong it is totally random, not necessarily anyone's fault. Like sickness, earthquakes, hurricanes, volcanoes.
Sometimes it is the fault of mankind in general, for abusing nature and its resources, or because of corruption and inequality.
Sometimes we bring things on ourselves or someone causes our pain or distress.
But in all cases we can see the hand of God if we will look for it. Not inflicting the problem, but supporting us through it. Whether our suffering is actually sent by God or caused by others (or ourselves) is largely irrelevant. We suffer much worse by agonising over it, worrying about 'why', dwelling on the injustice of it.
Whatever the reason for your suffering, God can use it - to strengthen your dependence on Him, to detach yourself from material things and your own wants and desires, and to strengthen your character. (See Romans 5:3-5, quoted in These things I know 5)
Other posts in this series:
2 The Kingdom of God
5 The Old Man
Strangers in the World
7 months ago