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
Call emergency services now if you have:
Trouble breathing, noisy breathing, or sudden throat swelling
Choking or an object blocking your airway
An inability to swallow your saliva, especially with drooling
Food stuck after swallowing and you cannot swallow liquids or saliva
And for anyone, someone who:
you believe has taken an overdose or swallowed something poisonous
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
2
Is any of this happening?
Be seen today
Seek same-day medical care if severe pain stops you from drinking enough.
You should also get urgent advice for rapidly worsening symptoms, a muffled voice, difficulty opening your mouth, one-sided throat swelling, marked neck swelling, or signs of dehydration.
Book an appointment sooner if food feels stuck, swallowing is becoming harder, you have unexplained weight loss, or you have persistent chest pain, hoarseness, or a neck lump.
And for anyone, someone who:
has abdominal pain that is severe, constant, or getting worse
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if the pain lasts longer than about a week, keeps returning, or has no clear improvement.
The article also says
People with a weakened immune system should seek medical advice early, particularly if they have fever, white patches, or pain behind the breastbone.
Every sign above is quoted from the sofidex article on Painful swallowing. If you are not sure, err upward — it is always reasonable to be checked.