The child is 1 year and 10 months old. For the last two to three weeks…

The child is 1 year and 10 months old. For the last two to three weeks, he often wakes up crying at night around 2 AM, as if he's scared or something hurts him. It's unclear. And he falls back asleep almost at 5 AM. During the day, everything is fine; he falls asleep normally at noon and sometimes even goes to bed by himself. But I can't understand what's happening at night.