I feel exhausted when walking short distances my heart races and i feel breathless also my sweat has been smelling sour i've had a e.c.g and blood pressure test which where both fine please help.

More tests: You need an echo to assess the strength of your heart and a blood count to rule out anemia. You need a chest x-ray to assess your lungs and pulse oximtry with exercise. There are many things that could be wrong including cardiomyopathy, asthma, anemia. Even malfunctioning kidneys (with uremia) could be causing your symptoms.

Cardiopulmonary: Your symptoms merit a careful cardiac and pulmonary examination, including history taking, physical examination, ekg, chest x-rays. Then it can be determined whether further testing, including spirometry, stress testing, echocardiogram and blood testing, might be appropriate for clarifying your symptoms.