In How Long, O Lord? Reflections on Suffering and Evil, Don Carson writes about “innocent suffering” in the book of Job:

The emphasis on Job’s goodness is meant to highlight the fact that there is a such a thing as innocent suffering.... [T]he link between suffering and retribution found in, say, Deuteronomy, Proverbs, and Romans, is never so mathematically rigid, so symmetrically precise, as to rule out the kind of suffering this book considers.... Although the Bible insists that all sinners will (eventually) suffer, it does not insist that each instance of suffering is retribution for sin. Doubtless if this were not a fallen world, there would be no suffering; but just because it is a fallen world, it does not follow that there is no innocent suffering. (140)