27f, hx fast HR after just walking (130), SOBOE, burning pain in top of chest when breathing in only. No dizziness. Chest infection or heart related?

SOB on exertion. At your age I suspect tracheobronchial etiology of your dyspnea. The rapid heart rate would be secondary to the exercise intolerance. An associated cough or wheeze would be diagnostic. If these symptoms persist or worsen you should be examined by a physician for diagnosis and treatment. Appropriate tests will be ordered.