re: OT runners, soreness between Calf and Ankle

Could be alot of different things, including slight strain to your soleus or minor tear or inflammation to your achilles. AS others have said, I would rest it and make sure it doesn't become chronic. If you don't rest and it becomes chronic, then it can take quite a while to heal.

I would RICE, and, as long as you aren't in pain, then do calf stretches multiple times daily, with some eccentric calf strengthening/raises daily, with icing and light massage of the achilles tendon area.