Psalm 126:1-6 ASV

The Psalmist realizes the blessings after the pain of captivity. They dreamed, laughed, shouted joyfully, and saw the great things God was doing. The joy came from the pain. Perspective was restored, but they were losing it again.
So here is the prayer, "Restore our captivity, O Lord." Bring the hardship and the pain back. Because that is the seed to bring the joyful harvest. Without the pain we don't see true joy. Now that is a tough prayer!