One sure thing about kids is they grow — and sometimes very quickly!

This can cause growing pains, bringing lots of discomfort to kids between the ages of three and 12.

Growing pains occur in a child's thighs, calves, shins, or behind the knees.

Some kids also have pain in their arms.

These aches usually happen in the late afternoon or during the night.

Growth hormone is emitted when kids sleep, which is one theory that could explain the timing of the symptoms.

While the cause of growing pains is unknown, some research has suggested overuse of limbs or poor posture may be related.  Sometimes, other pain syndromes accompany growing pains.

A new study found 76% of kids who experienced growing pains also had headaches five years later, compared to 22% of those who didn't have growing pains.

Treatment typically includes giving kids over-the-counter ibuprofen or acetaminophen, gentle massage and stretching.

Applying heat to the area can also help ease the hurt.

If the pain is persistent and severe, you should let your child's doctor know.

Though they're called "growing" pains, experts say symptoms are usually not worse during growth spurts, and the pain is not confined to growth areas of bones.

Some believe the discomfort may just be due to all the running, jumping, and climbing that active kids do on a daily basis.