Ok so the last few times I've tried to run I've had some pain in my lower left leg. It's in the rear, below my calf. I never feel it at all when I'm not running and only start feeling it about 25-30 minutes into a run. Once it starts it's quite painful and then I can only do short run/walk intervals. I know the default advice is see a doctor and I may do that if it doesn't improve.

I've been icing it, and took almost a week completely off running and it's the same as it has been the last 2 weeks or so. So it's not overuse (I only run ~15 mpw anyway) My routine and speed hasn't changed. Outside of shin splints the first month or so I haven't had any foot/leg problems.

I thought maybe my shoes are breaking down...I'm my original pair I started C25K with in June. Nike Pegasus (neutral) They have < 300 miles on them, but they are almost 6 months old and I'm pretty heavy. I've seen people say on here they can "feel" when their shoes are starting to go. Is this something that's consistent with that? I know everyone is different, just asking generally.

I've had this same injury happen to me, several times in the past, all during winter running.  If your injury is the same as mine, it feels like the cramp from hell and even though you're not running it still hurts somewhat.  My solution was not running for 2 weeks and then GRADUALLY work back up to my previous mileage.  A friend who works for Arrosti told me that it's actually a calf strain and while some of that wierd tape that people are now using, may help somewhat, the only real solution is too rest it.

SO42, are you a neutral runner, which is why you are in the Pegasus?  If so, that might be your problem.  The Pegasus is a good shoe, but it is not exactly the best shoe for a heavier runner, it is a bit lighter and less firm in the heel and midsole than some other cushioned/neutral shoes.  I am 206 and since I underpronate, I use cushion/neutral shoes also.  I tried the Pegasus, but it was just too 'spongey-feeling' for me and gave me problems and it will not give you as many miles as a more supportive shoe.  So I went to the Nimbus, which works great for me.  My podiatrist actually recommended it for me because it suits my foot type and also gives we heavier runners a bit more of a supportive ride.  Another good one for we fat-guy/bigger runners who need cushion shoes  is the Mizuno Wave Creation, which I have also used in the past to good effect.  However, of the two, for me the Nimbus gives me the better ride.

 

Hope you find the solution to your problem and are 100% again in no time!

Interesting. I tried on a pair of Nimbus one time, they were very snug on my heel, which I'm not used to. But maybe that's what I need. I assume I am neutral but I've never really been analyzed. If I do the "wet paper" test it looks like a normal arch, etc and I've never had any foot or knee problems through many years of sports and military. Then again I was much younger and lighter then.

Time to go get my gait analyzed and maybe try some more supportive shoes I guess