Thank you for your query,
Your son is having gastroenteritis
and it is 6 days duration.
Give sips of oral rehydrating solutions , coconut water, lemon water after each vomiting and loose motions in equal amounts to the losses to prevent dehydration
Because of colic, gastritis
component and increased motility of gut, the pain will occur and subsides after controlling the infection.
Consult your Pediatrician
for examination of your child and specific management.