@iats I think John has made a valid point that you should seek a medical opinion. It is very easy to think something isn't a big problem, and it's easy to guess wrong. You don't want to guess wrong about something that can have serious consequences if it needs urgent treatment. You need a doctor to evaluate if your arm and chest pain might be related to overly tight chest muscles, irritation around the lungs (possibly left over from a respiratory infection and coughing) or if it may be heart related.

I have had pleurisy and it did cause sharp pains with a cough after a respiratory infection. That was a long time ago and it eventually got better. Will you please seek a doctor's opinion?