Thank you for your query on Healthcare Magic.
There are many reasons for pain abdomen in children and at different times there may be a different cause for his pain depending on the involvement of type of organ.
At present as he is having significant prolonged pain abdomen and associated with vomiting
sensation it looking like an alarming problem.
He needs physical examination of his abdomen by a doctor and if required ultrasound
abdomen and pelvis at present.
I advise you to consult his pediatrician
as early as possible for the examination and the management of his pain abdomen.
Hope I have answered your query.