I suspect Precordial Catch Syndrome
, aka Texidor's Twinge, a very common complaint of benign chest pain
in children and young adults.
Generally, if you can control or moderate the symptom with chest wall movement, its not your heart. PCS is a suspected pinching of a nerve
in the chest wall that is aggravated with chest wall motion; such that when you take a deep breath, it makes it feel much worse. Usually resolves on its own in anything from several minutes to over an hour or two. There is no "cure" per se, but as it is usually self resolving and benign, its really nothing to worry about.
See your doctor, and ask him / her to consider this in their diagnosis.
I wish you well.