Stomach Pain, Vomiting On Eating, Nausea, Difficulty Breathing, Eye Blinking. Causes?

Hi, My son is 9 years (boy) old. from past one month he is suffering from the stomach ache & vomiting . I have shown him to many doctors with lot of testing, but my son is not alright. Though the vomiting has stopped, but the vomitish feeling has not yet stopped. He always feels like vomiting and ask for something to eat, so that he could vomit. The another problem which has recently started is that sometimes he is unable to breathe, and has started blinking his eyes most of the time. It would be helpful to tell me what the problem is and how it can be cured.Your suggestion would be helpful.