Can't sleep at night

My 5 yo kid is getting hard to sleep at night. Usually our TV screen time ends at 10pm. We go to bed around 10.30 pm. He always complained he couldn't sleep. I played a lullaby song every night to make him sleep. However, he still couldn't sleep. Sometimes, it will drag for 1 hour. It affected my sleep as well. How should I make him sleep better?