Acid Reflux (Heartburn); Common Signs & Emergency Symptoms

2. Sour taste

When the stomach acid backs upward to your mouth, the taste it leaves to it becomes bitter or sour. You may get a burning sensation in your mouth and throat as well. The reason behind soreness is the irritation of specific nerves that carry taste signals from the mouth to the brain. You may feel this sign, particularly in the morning because of the overnight backflow of the stomach contents.