I HAVE BEEN TO SEVERAL DOCTORS ABOUT MY SEVERE SOB

I HAVE BEEN TO SEVERAL DOCTORS ABOUT MY SEVERE SOB WITH EXERTION. LUNG DOCTORS SAY IT IS A HEART PROBLEM AND HEART DOCTORS SAY IT IS A LUNG PROBLEM... I HAVE SOB WHEN I DO ANYTHING THAT TAKES ENERGY! IF I WALK MORE THAN A FEW FEET, I AM PANTING. I HAVE TO STOP AND HAVE MY BREATHING AND HEART TO CATCH UP WITH EACH OTHER. THIS IS NOT A NEW PROBLEM
I HAVE SUFFERED WITH IT FOR 10 YEARS. I AM ON BREATHING MEDS, AND INHALERS. THEY DO NOT HELP WITH THE SOB. IF I PUSH A CART IN A STORE, I DO BETTER. AFTER I EAT, IT IS AWFUL! WHAT IS WRONG WIH ME???