L2 A 30 year old male chronic smoker, auto driver by occupation comes with complains of chest pain on right lower lateral side, and low grade fever. On examination he is emaciated, febrile, tachypnea. On auscultation there is diminished vesicular breath sound on right ISA and IAA, aegophony is heard at the upper border of diminished breath sound. What is the likely diagnosis? (1) Describe etiology and clinical features of the disease. (2) how will you investigate this patient? (3) Describe treatment and (4) Complications of this patient.(3+2+3+2)