Understanding Trials and Pain from an Islamic Perspective

Salam everyone, I've been reading the Quran (about a third of it so far) and I'm really drawn to Islam's teachings on morality and its clear concept of one God. It makes a lot of sense to me. But I'm wrestling with something many of us ponder: how do we reconcile the existence of an All-Powerful, All-Knowing, and Merciful Creator with the suffering we see in the world, like children facing serious illnesses or tragedies? Sometimes, it's tough to hold all these truths together. I deeply respect the faith, but this question is a real struggle for me. For those who have grappled with this, how do you find peace and understanding? I'd appreciate hearing your thoughts and insights. JazakAllah khair.