Chest tightness, shortness of breath, weakness, first of all, to rule out the cardiopulmonary causes, such as lung diseases, including bronchitis, bronchial asthma, chronic obstructive pulmonary disease, pneumonia, pulmonary stasis, pulmonary edema, or myasthenia gravis and the respiratory muscle paralysis. Next is cardiac, heart failure from various causes such as coronary artery disease, rheumatic heart disease, cardiomyopathy, etc., as well as pericardial tamponade, pulmonary tethering, pulmonary hypertension, and so on. Finally other causes can be considered as poisoning, such as diabetic ketoacidosis, organophosphorus poisoning, and so on. There is also cardiac neurosis which can be characterized by chest tightness, shortness of breath, weakness, and can be characterized by coldness around the body and twitching of the hands and feet. Most of them are caused by emotional excitement, leading to hyperventilation. Severe anemia can also cause chest tightness, shortness of breath and weakness. Hyperthyroidism can be just as severe with these symptoms and requires further tests such as cardiac ultrasound, EKG, lung CT, laboratory tests for nail function, and blood counts. There is also low potassium which can cause weakness and the cause can also be clarified by ionization tests.