#AskTheExpert Hello Doctor. Yesterday afternoon suddenly my child started crying. We couldn't understand why he was doing so. Firstly he was playing very nicely with us then suddenly started crying. He is 3 months old. I tried feeding him but he did not wanted milk. So we undressed him to see if anything is bothering him but no. So I made him sleep. Maybe he has not pooped for 2 days must be the reason, but then he pooped in the afternoon and I feed him and put him to bed. In the evening again he started crying suddenly. We thought he has not slept properly so we made sure he sleeps properly this time. But at night again he was playing and started crying. Would you please tell me what could be the reason?