Babies often fuss, cry, or pull away from the breast during the feeding because they need to burp.
A fast flow of milk can exacerbate this. They can also swallow more air when they are fussy or gulp down milk faster than normal if they are overly hungry.
Overfeeding or underfeeding: If the mother has a fast let down, the baby may get cranky due to choking or overfeeding. If the mother has a low milk supply, babies may get cranky due to hunger.
Gastroesophageal reflux: If your baby is crying a lot after every feeding, it may simply be a buildup of air swallowed while eating. Babies who spit up milk or curdled milk frequently can have a reflux issue.
Bottle-fed babies in particular may be more prone to swallowing a lot of air during feeding. This can trap gas in their stomachs and be uncomfortable. That is why pediatricians recommend stopping bottle feeding.