There are numerous causes why an infant is crying. Pain is an important cause of vomiting, but the pain need not be abdominal. It could be due to acute otitis media or a fracture or a urinary problem.
Pain and crying in an infant may be due to excessive wind caused by air swallowing during crying or feeding. If the baby is breastfed, then the air swallowing can be due to sucking too long on the breast or sucking on an empty breast, and if the baby is bottlefed it is almost always due to too small a hole in the teat. It is often followed by loud borborygmi (audible peristaltic sounds) and relief obtained by passing flatus per rectum. Rarely it can be due to intolerance to cow's milk protein, soya protein or other substances. If the crying is persistent, please get the baby examined by a pediatrician. The colic can be reduced by proper technique of feeding and burping after feeding.