4 months crying out of sudden

Hi Mummy, try observing what time and when does he usually cry all of a sudden. Watch for trigger cues. sometimes hunger pangs (usually will show when they start sucking their fists or turning inwards towards chest if breastfeeding) or trapped wind. check if there's no constipation and urine output is still good. Once you observe perhaps you might find a pattern that might cause the distress. If the crying is usually in the evenings or late night, try playing Surah Al-Quran near your child and close all windows during Maghrib. No harm trying this as well. hope it helps you mummy.