Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Seek emergency help for:
New, severe, or persistent chest pain, especially with sweating, faintness, breathlessness, or pain spreading to the arm, back, neck, or jaw
Sudden severe chest or upper abdominal pain
Repeated retching or vomiting with an inability to keep fluids down
Vomiting blood or material resembling coffee grounds
Black, sticky stools, particularly with weakness or dizziness
Severe pain with inability to swallow, marked abdominal swelling, or collapse
These symptoms can have causes other than a hiatal hernia.
Emergency assessment is important because symptoms of a heart problem, internal bleeding, or a trapped stomach can overlap.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Get prompt medical advice if food repeatedly sticks, swallowing becomes painful, you are losing weight without intending to, or you develop signs of anemia such as unusual fatigue, weakness, or breathlessness.
3
Does any of this apply?
Book an appointment
Arrange a routine medical appointment if you have frequent heartburn, repeated regurgitation, ongoing upper abdominal discomfort, or symptoms that disturb sleep despite self-care.
Also seek assessment for gradually worsening swallowing difficulty, unexplained tiredness, early fullness, or recurring vomiting.
Every sign above is quoted from the sofidex article on Hiatal hernia. If you are not sure, err upward — it is always reasonable to be checked.