Health-and-Age

I have had a c-t scan of my lungs, an echocardiagram, and a stress test performed to try and find the reason I swell in many areas of my body. My feet, ankles, stomach, wrists, fingers, neck and sometimes face & eyes swell for no medical reason so far. I have been on a diuretic for 3 years that only helps minimally. I also tire easily, have a smothering feeling when I breathe sometimes and feel like I'm not getting a full breath at times. I walk 1-2 miles six days a week, usually maintain a healthy diet and watch my alcohol intake. I have gained more than 50 lbs over the past 5 years or so. Some days the swelling makes me feel like I will break if I bend the swollen area (especially my face). I have acid reflux really bad and have been on Nexium for more than 3 years. My doctor is baffled and only contributes it to my salt intake, which I have always minimized. Why would this suddenly start about 4 years ago? I feel there has to be a medical reason. It's very frustrating never knowing what shoes or clothes I'm going to be able to wear from one day to the next. Also, some days are worse than others. Could someone please help?