foot and knee and leg are often cold?

My left foot and knee and leg are often cold (very cold even in hot weather) and and sometimes the right ones feel cold, less severe though, too. I had done many kinds of tests, MRI on head and spine, bone scan,cardio etc and no doctor could get me a clue. They did look at my foot leg and arms and did not think I have poor circulation. In the past 10 years I had done two cardio tests on the heart and the doctor said my heart works great and has no issue at all.

I did some self evaluation per some websites and found the only symptoms of poor circulation that I have are the cold feet, leg, knee and arm.

Now I want to confirm if I have poor curculation on the foot, leg, around knees and (left) arm. Which doctor I need to go to and what kind of tests should I do? In case I do have sort of poor circulation how can I heal it?