I Have Some Symptoms And Cannot Put My Finger On

I have some symptoms and cannot put my finger on the problem. I will just list them. Burning in the bottoms of my feet . They do swell sometimes. Decreased grip in my hands, always dropping things. Walking stairs feels like i have exercised for an hour and have muscle burn. I work retail and walk 10 to 20 thousand steps a shift. By the end of my day, I have increasing fatigue. My family doctor has no idea what could be the problem. Don't know what else to do. Thanks DA Summers