You're spot on with your previous post, but just wanted to add a note to anyone reading that if you've been having intermittent chest pain or discomfort for weeks/months, it still could be a heart problem (or reflux or a host of other things) that needs to be checked out. You could have a partial blockage of a coronary blood vessels (the blood vessels that provide blood/oxygen to the heart muscle itself) that provide insufficient blood flow, either when you're active, or randomly.
(this is not medical advice!)