The human condition would be my best short answer to that. I'm not familiar with the Jewish explanation of why things are as they are, and I'm uncertain of the Christian one, so basically I sit eternally in agnosticism.
Also I've been very hesitant taking on a faith due to years ago having very strong belief in New Age claptrap and then finding out all I invested in it was a farce. I wasn't easy coming back from that in terms of my ability to have faith anymore, for I have had a dread of not wanting to live a lie again.
I understand your position, as the Gemara Sanhedrin teaches, the seal of G-d Himself is truth.
The Jewish view of suffering in this world is a complex one. But I will try to give a short fit for the internet answer.
We approach our view of the world's troubles from certain foundations.
1. Is Hashem's perfection.
2. Human fallibility.
3. The purpose of evil in this world is for people to reject evil and choose good.
4. By choosing good they earn the reward they receive from Hashem.
5. It is rule of the universe that earned reward is more valued then unearned.
6. People who choose evil in this life will be punished in this life, and failing that in the world to come, Olam HaBah.
7. The vast majority of people are reincarnations, Gilgulim.
8. The purpose of reincarnation is to be given another chance to right the wrongs of your past life.
9. Those born into suffering are often being punished for past mistakes, as a process of cleansing the soul.
10. In time Hashem, G-d, will send a descendant of the Royal House of David, to perfect the world. This man will be known as the Messiah, Melech HaMashiach, literally the King G-d's anointed.
This is obviously an extremely shortened and simplified explanation of the Jewish view. If you have any questions or challenges I will do by best to respond.