I Have Pain And Burning Sensation In My Toes And

I have pain and burning sensation in my toes and feet. I also cannot tolerate heat anymore, I perspire profusely. Sweat runs down my face into my eyes, my shirt will be wet and the perspiration under my arms has a strong onion smell. I never had this problem prior to last year and have brought to my MD's attention. My sodium level is also low. Could these be related? and what can I do?