Lower leg pain just below calf and into lower calf (Read 822 times)

Last week at about mile 4 of a run, there was a mild pain in my lower inside leg between the calf and the ankle. At mile 5, I had to stop and stretch it out and walk a little and then run slowly to finish the 6 miler. The area below and going into the the calf was quite swollen afterwards. It was only mildly bothersome on two more runs during the week. Today, however, the pain made me stop and stretch it out after about 3/4 miles. I cut the run short and only ran 3 miles. I've checked out The Virtual Sports Injury Clinic and can't find anything that specifically points to what it is. Any ideas? Thank you.