ARE GROWING PAINS A REAL THING? The short answer is that yes, growing pains are real and usually harmless part of childhood. Though poorly understood, they are recognized as a common phenomenon occurring most often between the ages of 3 and 12. The pain is commonly felt in both legs, particularly at night with no clear cause of pain. As yet no one is able to explain why they happen but growing pains are thought to be a normal response of a growing body as it adapts to new heights, sizes, strengths and skills.