help with leg pain?

For the last year I have had numbness in my left thigh just above the knee.  It burns when I walk or stand.  I have had an MRI of my back and Knee nothing is wrong.  I have had steroid injections in my knee and back, doesn't help.  Seen a neurologist and taken those meds did not work.  It is not a blood clot either.  Today on the back of my upper left thigh just below my butt a small 3 inch rash appeared that burns and stings, looks kind of like razor burn did not