Hey, my son is 3 year old and 13. 5 kg and is quite active throughout the day. But every thrice a week. He wakes up crying in night and complaints about pain in both the legs. It has become his habit to wake up every other night and scream due to pain. Every time I give him some paracetamol and make him sleep. Its take about 2 hours for him to go back to sleep. I'm really worried. Don't like to give him medicine every time. But I don't have a choice. What's wrong with him.