Some people with early myocarditis don't have symptoms. Others have mild symptoms. Common myocarditis symptoms include: 
Chest pain
Fatigue
Swelling of the legs, ankles and feet
Rapid or irregular heartbeat (arrhythmias)
Shortness of breath, at rest or during activity
Light-headedness or feeling like you might faint
Flu-like symptoms such as headache, body aches, joint pain, fever or sore throat
 Sometimes, myocarditis symptoms are like a heart attack. If you are having unexplained chest pain and shortness of breath, seek emergency medical help. Myocarditis in children When children develop myocarditis, symptoms may include: 
Breathing difficulties
Chest pain
Fainting
Fever
Rapid breathing
Rapid or irregular heart rhythms (arrhythmias)
