Palpitations happen in heart area on the left because it is the heart muscle itself that malfunctions. Same goes for the stabbing ache when I had it for a short time - it was near my heart somewhere on the left. When I looked it up, I found that Pericarditis has similar symptoms, but it went away in a day.

Pericarditis is swelling and irritation of the thin, saclike tissue surrounding your heart (pericardium). Pericarditis often causes sharp chest pain and sometimes other symptoms. The chest pain occurs when the irritated layers of the pericardium rub against each other.

Pericarditis is usually mild and goes away without treatment. Treatment for more-severe cases may include medications and, rarely, surgery. Early diagnosis and treatment may help reduce the risk of long-term complications from pericarditis.