Hi
Your son must be having a bad virus going on for the past 2 weeks.
Did you see a doctor? If not, please have him seen by a
Pediatrician as its 2 weeks now.
Many viral illnesses present with aches everywhere and tummy pain too due to
gastritis.
Since both his intake and activity are not okay, I would suggest that you see a doctor soon, have basic blood tests like
Complete blood count, CRP done along with urine routine and get him treated accordingly.
Till you see your doctor, give him plenty of fluids- plain water, juice, milk, soups etc.
He might need oral
Acetaminophen in a dose of 15mg /kg/dose repeated 3 to 4 times a day for pain in his
limbs.
His tummy ache needs to be assessed by a doctor and treated accordingly.
Hope my answer helps you.
Wish a speedy recovery for your son.