A 56-year-old male presents with chest pain, fever (38°C), and cough for 3 days. He had a history of acute myocardial infarction (AMI) 1 month ago. Physical exam reveals pleural friction rub in the left lower chest and pericardial friction rub at the left sternal border (3rd-4th intercostal space). Chest X-ray (CXR) and echocardiogram (ECHO) show small pleural and pericardial effusions, with a small shadow in the left lower lung. What is the most likely diagnosis?