The reasons for uncomfortable stomach without sitting straight include gastritis and other physical diseases, overeating, hunger, mental illness and so on. 1. Physical disease: if gastritis, at this time, due to the damage of the stomach wall, do not sit straight stomach wall pulling will aggravate the pain in the stomach, so the stomach is uncomfortable. 2. Overeating: when the patient overeating, due to the rapid expansion of the stomach, sitting in an improper posture is easy to stimulate the stomach triggered discomfort. 3. Hunger: when the human body is hungry for a long time, the phenomenon of stomach discomfort will also occur. 4. Mental illness: If the patient has depression and other mental illnesses, these diseases can trigger gastrointestinal dysfunction, will also be upset stomach. Finally, if you do not sit up straight, please consult a doctor in time and follow the doctor’s instructions for active treatment.