Hi Doydie,
You've got me pretty well stumped on this one. I don't think it could be MS related but just having the edema on the bottoms of your feet is challenging.
Do you or do you think you may have diabetes? Although I would still think the edema would strike the whole foot rather than just the bottoms.
The only think I can suggest is to go visit your PCP and get his input on this. It may be something totally harmless and then again it may be an indicator of something more serious.
Keep us informed as your post is very interesting.