Brown Spots on Legs

I have had tons of light brown spots and clusters of brown discoloration appear on my legs from about two inches below the knee down to the ankle area. Also accompanied by constant swelling, especially the left leg. I have been to my doctor over the matter. She suggested possible early signs of some sort of heart or circulation trouble. So she sent me to the heart doctor, he checked out my heart and blood flow, he also checked to see if i had any clots in my legs as a result of all the swelling. They also did a nerve conduction test because on the left leg, in the outer thigh area is a section of muscle that is completely numb. Been that way for about 3-4 months now, shortly after which the spots started to occur, They appear to be covering more area, they aren't as bad on the right leg. All the test were fine, no sign of anything. The conclusion was to ware pressure hose while standing or walking, for the swelling and of course to lose weight. I also have an under active thyroid of which I am now taking medication for. Could there be any relation between the two? I stand up all day at work and I wear the hose, but my legs still swell, just not as bad. However, I am still concerned, it just doesn't seem right.