Okay, here is my theory on suffering. The Bible makes it clear that God is a God of justice.
Righteousness demands justice.
When the fall of man occurred, all of mankind became sinners because all were in Adam when he sinned. Our genetic material existed in Adam really and truly. I also suspect that we incurred some physiologic changes as a result of the fall. This idea of imputing guilt will come up again so keep it in mind. Of course this may not be the right answer at all but it is the best that I can do.