My son has been having stomach pains. no vomiting no nausea.?

Viral?: It sounds like a viral illness. If not better, you should be seen and evaluated for more serious problems.

Childhood belly pain: Abdominal discomfort in childhood occurs commonly--upwards of 20% of some age groups have it. A now archaic term that describes it best is RAP ("recurrent abdominal pain"). The rome 3 criteria, so helpful in adults in distinguishing functional versus organic problems, is not validated in kids. Nevertheless, some simple labs, x-rays, and directed questions may clarify whether to be concerned.