I've been training for a half marathon. 2 weeks ago I did my long run of 8 miles with no pain. A few days later I was doing a 5 mile run and this pain slowly built up in the back of my leg. it was a stabbing pain. It was higher than my ankle and and almost right below my calf. Yet, when I walked I could walk with no limp.

Even now when I walk there is no pain. I can pinch my Achilles tendon with no pain. When I stretch my my calf and achilles there is no pain.
Yet, when I run, the pain begins right there just past the base of my calf. It's almost dead center of the leg. When it first occurred it was like a stabbing pain.

I rested a week and a half with no running. Then yesterday I went for a 5.5 mile jog. It was a bit sore at first. Not stabbing, but more of an ache. Any time I came to a hill, I walked up the hill and commenced to running once at the top. After about 2 miles the pain was gone. When I finished the run I was doing a quarter mile cool down/walk. On the cool down the pain started back a little bit in the same place. Not a stabbing pain, but more of the dull ache.

After the run I took an ice batch followed by an ice pack treatment on the spot. Today I have been keeping it elevated and using ice treatment.

I am thinking of taking another 1.5 week to 2 weeks off. I have my half marathon on March 1st. I thought it was an achilles tendinitis, but it seems to high. I don't think it's compartment syndrome. Any ideas as to what it is and what I should do?