I got this with both my babies too, but only in the car! I would sit in the passenger seat and just be bouncing! It drove me crazy. (We've got a little car - no room to stretch, really, so long trips when I was pregnant were pretty awful.) Sorry, I also have no suggestions for relief, except to move the legs and stretch when you need to. You definitely have my sympathy. At least you know it will end, eventually....
All the best!