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 care now for:
Sudden, severe, or rapidly worsening pain
A firm, very tender bulge that will not flatten
Red, purple, dark, or otherwise changed skin over the bulge
Repeated vomiting or a swollen abdomen
Inability to pass stool or gas with abdominal pain
Vomiting blood, black stools, fainting, or severe weakness
New or severe chest pressure, especially with breathlessness, sweating, nausea, or pain spreading to the arm, jaw, back, or shoulder, needs emergency assessment.
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
Seek prompt medical advice if a hernia becomes newly painful, more difficult to move back when it was previously reducible, or associated with nausea or a change in bowel movements.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you notice a new groin or abdominal lump, recurring pain with lifting or coughing, or possible hiatus hernia symptoms that do not settle.
A previously assessed hernia should also be reviewed if it is steadily enlarging or interfering with work, sleep, exercise, or daily activities.
The article also says
Chest pain can have causes other than a hiatus hernia.
Every sign above is quoted from the sofidex article on Hernia. If you are not sure, err upward — it is always reasonable to be checked.