Dull chest pain could be a symptom of many different things. Many organs and tissue are in the chest; heart, lung, gall bladder, esophagus, muscles/cartilage and anyone could be a suspect. So, too anxiety can cause actual physical symptoms. Frequently pain that worsens before or after eating or with deep breathing or movement can isolate where the pain originates and, therefore, the cause.
You didn't mention your age, however, mentioned that you work out frequently. Unfortunately,largely due to genetics, a healthy lifestyle including diet and exercise do not necessarily absolve a person from heart disease and women are being diagnosed younger and younger (even in their 30's). Also, women can have "atypical" chest pain (meaning not the sharp pain in the center of the chest type pain that we usually associate with heart problems). The bottom line is that you should go see your doctor. Examination of your symptoms and tests can rule out or help alleviate your concerns.