Why do bad things happen to good people? Because you take language literally.
In 1981, Harold S. Kushner wrote When Bad Things Happen to Good People, in which he explained that bad things happen to good people basically because the universe is imperfect and largely impersonal. God is good, and He's there to help, but He's not almighty. The story of the garden in Eden is another attempt to explain why good people suffer bad things. Reincarnation offers an explanation for this paradox as well.
My explanation for why good things happen to bad people is that one needs no explanation. In words, the concepts of "good" and "bad" are opposites. It sounds like a paradox that bad things would happen to good people. But in this case, "bad" and "good" aren't really opposites. In this context, "bad" means "painful" and "good" means "esteemed for moral character." The question of "Why do painful things happen to people who are esteemed for their moral character?" doesn't sound paradoxical. The answer is that painful things happen to animals whether they're esteemed for their moral character or not.
One can use the terms "good" and "bad" as actual opposites to form meaningful paradoxes. "Why are so many people who do bad deeds considered to be good?" "Why is behavior that was once considered good now considered bad?"
But the question about bad things and good people is a false paradox. The question only seems to need an answer if you take the terms "good" and "bad" too seriously.
Reduce (or is it expand? I guess it is) the question to "Why do bad things happen to people?" Then: "Why do bad things happen?" Then: "Why do things happen?"
Now you've got a question.
Here's my answer: No Good Reason.