What Causes Chronic Abdominal Pain With Anal Itching?

My son has been complaining of a stomach ache for approximately 4 weeks. He is six years of age and complains on a daily basis that his stomach aches. He points to the middle section of his stomach. He also complains of being itchy all over and he has an itchy anus. Can you tell me if there may be any relation to his ailments.