If you think about it, the problem is one of time. There doesn't seem to be enough time in a human life to "deserve" the "punishment" some people have to endure. Especially concerning children who suffer.
The answer to this paradox, traditionally, across the globe, is karma and reincarnation.
The idea being that you're not your body - you're a soul, which God give a body, over and over and over again, unitl you get it right.
Upside, is this makes sense of all the apparently unfair duffering in the world, AND creates a situation where everyone, sooner or later, reaches heaven - which supports the idea of a God of infinite love who will not - ultimately - let any of His children fail.
Downside?
This theory undermines the authority of the Church, and the threat of permanent hell forever.
Many research sources support the idea that reincarnation was a part of the early Church, and that Jesus taught it: Reincarnation and the Bible.
On the other hand, eight hundred years ago the Catholic Church slaughtered a half-million people to eradicate the "heresy" of gnosticism, which included reincarnation, and to this day will stick it's chin out and assert that every single one of of those people deserved to die at the point of a sword because of their reincarnational beliefs (among other things).
Go ahead, research this - challenge a Catholic on gnostic reincarnation, and thank God the Constitution prevents them from being in charge of what happens to you.
So decide for yourself.
Sorry friend, people can’t make something up even if they want it to be true. God has a plan and He has revealed it.
Read Hebrews 9:23
Catechism of the Catholic Church
paragraph 1013
Death is the end of man’s earthly pilgrimage, of the time of grace and mercy which God offers him so as to work out his earthly life in keeping with the divine plan, and to decide his ultimate destiny. When “the single course of our earthly life” is completed,586 we shall not return to other earthly lives: “It is appointed for men to die once.”587 There is no “reincarnation” after death.