At 28, you are quite young to have a heart condition, unless you have one from birth [congenital] or childhood [rheumatic]. I am sure you do not have neither of these two.
Bulimia is not as likely to cause heart failure and cardiac death as anorexia. Those who take frequent purgation and induce vomits, may suffer low potassium levels and sudden cardiac death. Excess nutrition from bulimia may have caused hypercholesterolemia etc but now that you are out of it there is no imminent threat.
As for chest pain, any pain that increases on coughing, sneezing, turning, or deep breathing generally is not from the heart. This could either be a muscular pain or pain from the lung memrane called pleura.
If the pain is very consistent is may be worthwhile to check with your doctor if some chest x ray is required.
But stop worrying about heart failure at your age!
Dr Apurva C Madia
Consultant Cardiologist and physician