You don't state your age, sex, occupation, habits, smoking history, family history, weight, etc. Nor do you define the nature of the chest pain, where in the chest it occurs, when it occurs, what makes it worse, what makes it less, what you mean when you say you have "dyspnea", etc.
Consequently, I am sorry but I am unable to comment on your symptoms and your medication of diltiazem and nitrates.
Please be aware that I am unable to diagnose medical conditions online.