<s>[INST] Today I experienced a sudden occurrence of shallow breathing, breathing was not painful but it felt as if pressure around my chest was preventing me from inhaling deeply. Probably as a result of a decerase in oxygen level I became lightheaded and shaky on my feet [/INST] Hellowelcome to ChatDoctorwell there are 3 possibilities for your symptoms of sudden onset shortness of breath along with a feeling of pressure around chest--(1) AN UNDERLYING HEART DISEASE such as acute myocardial infarction, valvular heart disease, left ventricular failure etc. (2) AN UNDERLYING DISORDER OF THE RESPIRATORY TRACT INCLUDING LUNGS such as obstruction of the airways, bronchial asthma, pulmonary edema, pleural effusion, pleurisy, pneumothorax etc.(3) METABOLIC DISORDERS such as uremia, diabetes, hypokalemia etc.(4) MUSCULOSKELETAL like Costco Chat Doctor. E ACID BLOOD GAS ANALYSIS(5) PFT i.e. PULMONARY FUNCTION TESTS(6) X-ray OF CHEST(7) ECG(8) Echocardiography soon as you get these tests done, you can send us a scanned copy of all your reports for detailed evaluation, or you can consult your family doctor so that appropriate treatment can be started if required along with any necessary instructions and precautions hope you find my advice to be helpful take careChatDoctor.... </s>