Acidity is commonly known as heartburn. Hydrochloric acid is present in the stomach which helps in efficient digestion of food and protect the growth of unwanted bacteria. So when there is an excessive production of acid by gastric glands of stomach, then it causes acidity.
Due to over secretion of gastric juices, there is disruption in the lining of the upper part of small intestine. In some cases ulcers can be the cause of cancer.
Dyspepsia is the narrowing of oesopahus which creates the sensation of food being stuck in throat. It occurs after taking meals and is brought by excess abdominal pressure. It usually occurs at night when individual lying down on the bed and there is burning pain in the chest.