Husband has had a cold n cough 4 weeks n now the left hand side underneath the rib cage is swollen. has had pneumonia before. what can it be?

See a doctor: Could be many things including that the reason for the cough is not in the lungs but in the abdomen which is leading to swelling. The spleen is located in this area and could swell with certain infection or other conditions. Best to be seen in person.

Consider mononucleio: Infectious mononucleiosis caused esptein barr virus cause splenomegaly and prolonged could symptoms talk to his doctor.