hello there. acidity can be caused by certain foods, stress, smoking, peptic ulcer disease etc. follow this advice. 1. drink lots of water. 2. have smaller and more frequent meals. 3. don't eat oily or spicy foods and avoid known foods which cause such a problem. 4. don't sleep immediately after consuming food. have food atleast 2 hours before sleep. 5. practice yoga/ meditation. 6. avoid tea, coffee or carbonated drinks. 7. if you are a smoker, quit smoking. if it still persists, take a antacid and consult your doctor. you may need a endoscopy also. regards