I Have Seen Several Physicans For This Problem And No

I have seen several physicans for this problem and no one is able to tell me what is going on. hopefully you can. I am diabetic to begin with. Several ti,es a day my legs up to my knees get bright red and swell and burn awful and sometimes burns up in my groin. Ive been told it can be neuropathy or veinous insuffency or gout and I have been treated for all but to no avail.. Can you shine a light on this? thanks