What are the symptoms of a strangulated hiatus hernia?

A few. Usually chest pain and pressure, associated with the inability to eat, and / or vomiting. The vomiting is frequently in the form wretching without liquid or good coming up, or "dry heaves". Could also be vomiting blood. This represents an emergency, life threatening situation. .
See below. Strangulated hiatal hernia is a life-threatening surgical emergency and must be corrected as soon as possible. Symptoms can include upper abdominal and chest pain, typically severe and unrelenting. Nausea and vomiting are present in addition to some difficulty breathing. Tachycardia and tachypnea can occur, especially with gastric necrosis, which may progress to sepsis and cardiovascular collapse.