I've never tried but I've heard alot of people say about magnesium spray for growing pains and adding more magnesium into their diet. Could be worth a try? I know some children can get really bad growing pains. I remember in secondary school going to the nurses office with pains in my knees and groin

It’s growing pains my daughter gets it bad I give her Motrin and put a pressure knee high sock on her I used to get it too they actually say that it’s fibromyalgia 🤷🏻‍♀️ give him some Tylenol or Motrin when he complains

I used to get pain in the backs of my knees when I was little. If I remember rightly it used to be when I'd done a lot of walking that it was worse. I can remember my parents said it was growing pains back then. Can't remember when it stopped but I no longer get that pain, I have noticed that as an adult my legs hyper extend and I get a lot of calf cramping. Just a thought but watch how little one stands and see if he stands with legs so straight they bend back at knee. Or if he stands with knees flexed. Could be over extension leading to muscles getting tired?