The temple destroyed . . . God’s people captive . . . distress of every kind on every hand . . .
Those are the conditions under which the writer of Lamentations 22 wrote:

His mercies never end, they are new every morning; great is Your faithfulness.

Do you believe it, Christian? If not; why not? May I suggest a reason?
You have trouble singing the hymn based on this verse because you don’t look for those mercies every morning! Jeremiah (the probable author of these words) looked—and he found! If you are on the lookout, you too will do so. How about it? Do you need a coffee “fix” in the morning, or a wake-up call to explore God’s mercies?