hi
with your question I understood that you are having problems on left side of chest and specifically near bottom 2 ribs and whenever you don't eat healthy food
In your case I will consider that you might be suffering from acid peptic disease
reflux disease and also oseophagal spasm
as I understand that sometimes you have to eat junk food means either your work schedule or other commitments don't let you eat healthy
when we indulge in these foods which are increase in oil and spices
empty stomach, unhealthy meal and work
stress all tend to increase in acid content of stomach
due to increase in this acid it tend to sometimes reflux back in food pipe and due to which food pipe or oesophagus tends to have spasm
these spasmodic contraction of lower part of food pipe you are experiencing
as you have no history of pain with activities I will consider
heart disease less likely
Please do consult a internal medicine specialist for evaluation and starting you on proper treatment
prolong reflux in food pipe can lead to changes which can lead to bad consequences