Does lung pain during the flu warrant immediate (i.e. an urgent care) visit? fever is low; history of confirmed pneumonia in the last 6 months.

Yes: If you are having chest pain with a cold or flu, it might have spread to become a bronchitis or pneumonia and does require an evaluation.

Well,....: It depends on the severity of the pain and any associated symptoms along with your underlying medical history. It at the least warrants a call to your Primary care Doctor who knows you best and can ascertain better whether you should see an Urgicare health provider now or wait to see them tomorrow, etc. best wishes.

Lung pain: I'm not sure what you mean by "lung pain" and if it is actually chest pain, in which case yes you should seek medical attention urgently especially if you are having any dyspnea or shortness of breath.