I was told by my physio that one of the problems with ms was that your muscles often didn't relax when you want them to. This can lead to tightness in the calf muscles which can twist your feet.
He gave me stretching exercises and I will attempt to explain them in text....
Stand 2-3ft from a wall (arms length) and put one leg out behind you pressing the foot firmly on the ground.
Bend your other kneed forward and support yourself on the wall with your hands.
Keep the stretching leg straight and your foot on the ground, if your foot is not flat it won't work. Push the stretching leg as far back as you can, all the time keeping your foot firmly pushed onto the ground.
Keep your head up don't look to the floor face the wall.
Hold the position for a minute, you should feel your calf muscle tingling which is the muscle working out the tightness within it. At the end of the minute, change legs and repeat.
Like this >> http://www.frankfortphysicaltherapy.com/assets/health_topics/standing-stretch.jpg
When I do this I do feel a difference in the movement of my feet, they loosen up and don't twist so much (my right foot tends to penguin out otherwise).
I don't know if this is your problem, or if you can stand well enough to do these exercises but it's worth a try
Hope you're feeling better soon