is he passing stools? this is a very important question because if he is not then it may point to obstruction. another possibility is that there may be some mild gastritis. you can manage the pain by giving syrup colicaid (simethicone) 5 ml only when there is the pain. for the vomiting you can give syrup ondem (ondansetron) 5 ml thrice a day for three days. wait for at least half an hour after giving ondem to give any food or water. i would also prefer if you get him evaluated physically since he is lethargic you said. he may be dehydrated. for further information consult a paediatrician online --> <link>
my 4 year old has stomach pain. what is he suffering from?