So when we celebrate Christmas and rejoice in it, we are at the same time celebrating the death of Jesus and rejoicing his pain. This must sound ridiculous, but we do exactly that in Holy Communion, receiving the body and blood of Jesus. Our joy and salvation comes from the pain of God, the pain of Jesus. But Jesus allows it to be so.
And we can learn that no difficulty exists independently, no joy exists independently. They are always mixed together and related to each other: but if we hold on to Jesus, the joy conquers the difficulty. Christmas is its clear example and symbol.
God knows pain, as well as Jesus does. And that is the reason why those who have pain in their lives now are in the very middle of the grace of Christmas. Nobody is excluded from this grace.