Belching is a normal process and results from swallowed air accumulating in the stomach. The air can either be belched back or can be passed out of the stomach into the small intestine and be subsequently passed as rectal gas (flatus).
Bloating refers to a sense of fullness in the upper abdomen. This can be influenced by gas and/or food accumulation in the stomach. Some patients experience the symptom with normal amounts of gastric gas.
Flatulence refers to the passage of rectal gas. The gas is generally a combination of swallowed air and gas produced by the action of colon bacteria on undigested carbohydrates.
Gas which accumulates in the right upper portion of the colon can lead to pain which could seem like gallbladder pain. Gas which accumulates in the left upper portion of the colon can radiate up to the chest and seem like cardiac pain.