Most people find their hiatal hernia while looking for something else

The diaphragm is the thin muscle separating the chest from the abdomen, and
one of its jobs is keeping stomach acid out of the oesophagus. A hiatal hernia
is the upper part of the stomach bulging up through an opening in it — and
with the barrier compromised, acid gets up more easily.

That leaking is GERD, gastro-oesophageal reflux disease, and it is how the
hernia makes itself felt: heartburn, difficulty swallowing, a dry cough, bad
breath, nausea or vomiting, breathing problems, and the wearing away of tooth
enamel.

Why it happens, and to whom

Often the cause is unknown. It may be weakness in the surrounding muscles;
sometimes it is an injury or a birth defect.

How it turns up

People usually discover a hiatal hernia while being tested for something
else — GERD, heartburn, chest pain or abdominal pain. The tests are a chest
x-ray, an x-ray with a barium swallow, or an upper endoscopy.

Treatment, starting with none

If it causes no symptoms or problems, it needs no treatment. That is the
first line, and it applies to a great many of them.

Where there are symptoms, the order is:

1. Lifestyle changes — small meals, avoiding the foods that set it off,
   not smoking, not drinking alcohol, losing weight.
2. Antacids or other medicines, on your provider's recommendation.
3. Surgery, if those do not help.

*Source: National Institute of Diabetes and Digestive and Kidney Diseases,
via MedlinePlus.*