Thank you for your question, There are many reasons for chest pain such as gastrointestinal (about 40%), coronary artery disease (around 30%), musculoskeletal (about 25%), and other causes (which potentially mimic chest pain including pericarditis, pulmonary embolism, pneumonia, lung cancer, and aortic aneurysms,etc). Given that you have mastitis while Breast-Feeding,it could simulate chest pain and cardiac symptoms occasionally. However, additional symptoms presented by you has to be taken into account in terms of cardiac stable angina. To me, the point is you did not mentioned that the pain is related to a moderate or severe physical activity and you also stated that your pain is not vague in your chest region. Therefore, according to my experience , presumably your pain has another source and is rarely relevant to an Angina Pectoris. To rule out 100% a cardiac pain source: 1.     Refer to your doctor for physical exam to assess the source of your chest pain. 2.     You may need some test specialized and made after cardiologist visit such as Electrocardiogram (ECG), Blood tests, Chest X-ray, Echocardiogram, Cardiac stress tests, Coronary catheterization (angiogram) and modern CT scan specialized for chest pain assessment. 3. In case of facing to several cardiac signs and symptoms such as dyspnea, chest pain while doing an activity or permanent pain, nausea and dizziness, hemodynamic instability ( BP change), history of smoking and alcoholism, vague and referral pain in chest region, history of heart disease and TNG positive response you may need an immediate hospitalization. Hope you get well soon, Regards