Bodybuilding captures the whole essence of growth in a nutshell. We work our muscles until they hurt and over time, through the pain, muscles grow.
If pain is the secret of growth, then you have to do that thing you were born to do until it hurts. Write until it hurts. Run until it hurts. Talk to new customers until it hurts. Otherwise, growth will remain elusive.
The choice to always be at the edge of the maximum amount of pain you can manage becomes the choice to grow.