What Causes Painfully Swollen Legs With Throbbing Sensation?

During the past three years I have had a condition that seems to get progressively more difficult to tolerate as it not only feels painful, but also contributes to some lack of coordination. My feet will swell, become hot, feel very painful in a sharp and throbbing ways and have sharp piercing feelings from the bottoms of my feet and on the sides of legs. I have been to neurologists, rheumatoligists here and outside my state, had a myriad of tests including glucose tolerance tests all of which are normal. Tried accupuncture, tens units and physical therapy all to no avail finally relying on pain management which is no solution to me. Any ideas?