One of the most important things to personal growth is expanding the zone of comfort. To explore where comfort ends, and what happens in oneself there.
There are millions of ways to do that, and all of them are quite individual. Most of your discomforts are comfortable to me, and vice versa. Because of that, you’ll need to find out how to challenge yourself to a discomfort yourself.
What’s important to notice though, is that you do it. And that you’ll always grow from getting comfortable with something that you’ve previously been uncomfortable with.