What conditions cause heartburn, chest tightness, and the feeling that something's caught in my throat?

Anyone suffering from shortness of breath/difficulty breathing or chest pain/tightness should visit their doctor for urgent assessment. If the symptoms are severe or persistent, I usually advise my patients to go to the emergency department for further tests. If you are currently suffering from these symptoms, I advise you to stop consulting Dr Google and head down to your nearest doctor now. A variety of conditions can cause difficulty breathing and/or chest pain.

First and foremost, I would strongly advise you to seek immediate medical/ dental attention in view of your chest tightness and breathlessness. That, on it's own warrants some urgent attention in my opinion. There are many other possible causes of those symptoms besides the dental abscess that you described. In severe dental abscesses, the infection can sometimes track down to the neck and chest areas which we sometimes refer to as cellulitis. In very severe cases, it can lead to a condition called Ludwig's Angina.