If God exist then why people who didn't do any crime or Sin (particularly children or new born baby) are getting deadly disease? Because The pain they are getting is their own pain that God is not feeling instead of them.
Your premise is that God is a good being. But already the bible shows us that if God exists then he is certainly not a good being in the sense of humans, but either indifferent or deliberately bad. (Thererfore it would be better if he does not exist.)
As already the bible shows us God cannot simultaneously be omniscient and infinitely merciful:
Tree of knowledge amidsts the Garden of Eden
Creation of female and snake
Order to Abraham to sacrifice his son
Plagues and ruin of the Egypts
Israel's sons kill Sichem's men and rob the town but God managed that they did not get punished.
Every torture of a living being
But God is certainly not even omnipotent. Why did he need 6 days (and another day of rest) to create what an omnipotent God would have accomplished immediately?
It is clear that, if he exists, not all his properties are infinite (consider the scholastic proof that he cannot make a stone so heavy that he cannot lift it or the other way round).
If he exists he can be understood like a player of games like Age of Empires which would be boring if everything evolved without conflicts.
So the answer to your question is: Your premise is false.