How can you tell if what you're feeling is pleurisy or pericarditis?

Let me help: Pleurisy is an inflammation of the pleura, the lining of the pleural cavity surrounding the lungs.The inflamed pleural layers rub against each other every time the lungs expand to breathe in air. This can cause severe sharp pain with inhalation. In pericarditis characteristic chest pain is often present. Which is relieved by sitting up and bending forward and worsened by lying down or inspiration.

Deep breath: Pleurisy pain is usually felt during deep breathing ... Pericarditis is usually more constant ...