My DS had this when he was 5. he had abdo pain,slight temp,"change" in bowel habit,all usual signs,central pain which moves over to the left side eventually.
We spent a night in A&E, and childrens ward,and they decided it was "Mesenteric Adenitis" a weird similar pain,often called Viral,but definitely not Appendicitis.
3 weeks later we went again,stayed in,spent next day on Childrens Ward, whilst we waited for Theatre slot,eventually he had the op,and it had been inflammed.
He's now 12 and seems to suffer from similar pain,which I'm beginning to think is IBS.....
peppermint seems to help as does Windeze tabs.
Still yet to work out the trigger.
most Abdo pain in kids can be Constipation,their tums will be tender,but a GP will feel hard faeces on examination.
even though he may have been doing lots of No 2's,What was the consistency like?(sorry TMI)
If it was hard,or like Rabbit droppings,then it could be constipation,even Diarrhoea can be constipation,believe it or not!
After the 24 hours,Try simple remedies for constipation such as lots of water,orange juice/fruit,beans etc.
If that doesn't help see GP again.
If he does go to No 2 properly,you'll have ruled that out,and Appendix's can "grumble" and then get better,and come back again later on.
Sorry not much help.....