Thanks for query,
Your child might have infantile colic
and gastric upset,
You require to change the diet schedule.
apart from breast feeding star some solid food like meshed rice,dal,curd starting with one teaspoonfull to one table spoonfull,
You can give fresh fruit juice,he will like the taste and do not vomit.
You can give antispsmodic drops.
if problem persist,consult pediatrician