The sensation was as if my right lower leg has turned to stone. The pain stayed with me as I continued running--one problem with running in extreme cold is that stopping is usually a very bad idea--and the pain eased a bit. I pressed on with training for another two weeks until the pain was too debilitating to continue. I haven't run in days (this problem can sideline you for days or weeks).
And so I've been soaking my legs in hot water, taking ibuprofen with muscle relaxer and stretching. I've also stopped my protein and creatine supplements and eschewed my attempt to get more "cut". It seems ludicrous now that I ever contemplated gaining weight while training for a marathon. I have, as a result, lost 4 pounds this week.
My next run is scheduled for Monday. I intend to do a graded (run/walk) return. Let's see how that goes!