So we should never ask why in the sense of demanding that God explain or justify His actions or what He permits in our lives...When I say we should never ask why, I am not talking about the reactive and spontaneous cry of anguish when calamity first befalls us or one we love. Rather, I am speaking of the persistent and demanding why that has an accusatory tone toward God in it. The former is natural human reaction; the latter is a sinful human reaction. Three of the psalms begin with why:
"Why, O LORD do you stand far off?"
"Why have you forsaken me?"
"Why have you rejected us forever?"
(Psalms 10, 22, 74)
But each of these psalms ends on a note of trust in God. The Psalm writers did not allow their whys to drag on. They did not allow them to take root and grow into accusations against God. Their whys were really cries of anguish, a natural reaction to pain.
From chapter eight in Trusting God by Jerry Bridges.