5 years old son when asked complains about minor stomach pain for about a month now.otherwise he seems ok except vomiting episode 3 weeks ago or so??

Vague issue: Abdominal discomfort always has 3 inputs. The tissues themselves that may be injured/inflamed by an event; the brains sensory pain response& the effect of the diet. Some people become intolerant transiently to some foods after a stomach virus and or may be intolerant to some foods to begin with. Many of these will pass in time, but when they persist clarification may need thorough evaluation