Burning leg sensations + extreme fatigue

For over 7 months now I have had a burning sensation in my legs. It started with the left leg initially, and the toes on my left foot are purple most of the time, with some swelling of the foot/ankle region.
The pain is now in both legs, predominantly shin area. I am very, very tired all the time too.
Have ruled out circulation, brain tumor, dr's are now looking at automimmune diseases, including MS.
Any input would be appreciated!
P.S. Not sure if this is related or not, but my right clavicle is swollen and seems to be increasing in size lately