Welcome to HCM. Most likely it is due to indigestion called dyspepsia. There might be IBS and there is no any specific cause for it. It usually occurs due to disturbed diet pattern,oily,spicy food,disturbed sleep pattern,stress,anxiety. Drink more water and other liquids like fruit juices,lemon water,coconut water,buttermilk. Eat more liquid,simple,high fiber diet. Avoid stress. Eat small frequent meals. Take pantoprazole with cinitapride. Enzyme and lactic acid bacillus will be helpful. Consult your doctor for further guidance and medical management.