Have been having acid indigestion. is heartburn/acid caused by bacteria in the colon or stomach? or some other cause?

Possible bacteria: Heartburn, or esophageal reflux disease, is caused by stomach acid irritating the esophagus. Ulcers, or erosion of the stomach lining, are caused by acid and a bacterial infection, helicobacter pylori. The bacteria is thought to weaken the acid-resistant stomach lining, and is usually treated with a combination of antibiotics and an acid reducing medication. See your doctor if you have symptoms.

Made by you: The acid is produced naturally by glands in your stomach. They are there to add the acid to prepare it for the digestive enzymes added as food is processed. The burn happens when some of the acid backwashes into your swallow tube. Caffeine & nicotine are chemicals which prevent the stomach entrance from closing tight. Laying down after a meal adds pressure to backwash.