upper burning legs

last may i had a viral or bacterial infection,which lasted for 6wks, during that time i would be extremely cold &burning up at the same time,that happened about 3 times in may,then in july i had the hot &cold again, but only once,in sept. i started getting the burning in my upper front thighs,come jan. 5 times that month, i would stay either hot 4 ,2hrs,or cold  4, 2hrs,or sometimes both at the same time,havent had anything lately, except the burning 24-7. went to my dr. he did a thyroid test , that was fine,said he doesn,t know whats causeing the burning , but put me on amitriptyline,come back in a month.so can u tell me ,if this is all related.    norma