About A Week Ago I Started Getting Numbness In Both

about a week ago I started getting numbness in both big toes and now its also on the balls of my feet. I am a 56 year old female with no problems- It doesn't hurt - I can dance the nigth away - I just feel like both feet are numb. I have checked into MS but it wouldn't be both feet at the same time and so I am thinking nerve- maybe a pinched nerve in my back? How do you find out if that is what it is? Both toes and then feet at the same time????