Well, I doubt it is a heart pain actually. If the heart was the cause of pain, then it will be referred to your left arm, shoulder and sometime the lower part of the left side of your jaw, in other words you won't feel pain in your chest. But if the pain is like a sting in your chest and usually occurs with inhalation then I would say it is mild pleurisy
(inflammation of the pleural membrane) which is not a serious condition and happens to me all the time.
Still I advice you to consult a REAL doctor mesh kalam ay 7ad mel share3 masalan zaye keda :D
We alf salama..