hello sir, there could be many reasons for your breathlessness. commonly it would be related to heart, lung or renal disorders. as your breathlessness is aggravating on climbing stairs first make sure you don t have any heart disease. it s generally associated with breathlessness on exertion in initial stages and later even at rest and more in the nights and on lying flat. simple tests like ECG and chest x-ray are good enough for screening. next cause could be a lung disease where you would be coughing a lot of sputum. could be an hyperactive airway disorder like asthma or inflammatory like COPD or infections like pneumonia or tuberculosis or occupational diseases. to differentiate from heart and lung disease best way is to get a blood test for BNP levels. if they are normal then it rules out your heart disease. it s it s raised significantly then consult cardiologist or get an echocardiography scan for your heart. if it s the lung disease then it again can be because of hyperactive airway for which inhalers are needed to prevent bronchospasm. and if infection then optimal antibiotics should be sufficient. get your sputum checked for infection (culture and sensitivity test) before taking antibiotics. so that they can help us to find out appropriate antibiotics for your infection. renal is not as common as the heart and lung. just check your daily urine output if it s more than 500 ml then ignore .if less then get renal function tests and consult a nephrologist. so I suggest you to get a BNP level test ( because taking lot of fluids could be harmful in heart disease, so make sure that you have no heart disease before that) and then go accordingly. hope this information helps you.