I'm just coming back into running, and I've consciously changed my running style to do so, It's going ok, but I've noticed that after a longer run I sonetimes wake up next day with the sensation of my achilles twitching, and it feels almost as if someone is gently flicking it. It wears off after a while but it isn't very pleasant while it lasts; is it just a case of making sure I stretch them properly and keep them nice and flexible? I've gone over to minimalist shoes and I know that it can overwork the achilles if you don't build gradually - I thought I WAS building gradually?!