Pericarditis

Pericarditis is swelling and irritation of the thin, saclike tissue surrounding your heart (pericardium). Pericarditis can cause sharp chest pain that gets worse when you cough, lie down or take a deep breath.

Pericarditis is usually mild and goes away without treatment. If it's severe, you may need medication or, rarely, surgery.

It may be difficult to tell the difference between sudden (acute) pericarditis and pain due to a heart attack. If you have sudden, unexplained chest pain, seek emergency medical help.