Rest -- aborted run

I didn't mention an ache I've had in the last couple of runs. In my lower calf, maybe 5 to 6 inches from my heel, to the inside (medial side?) of my achilles, I've had an annoying mild pain. I thought it might be from me riding the outside edge of my foot and the inside part of my calf was cramping? Anyway this morning it was worse, so I cut off my run after two minutes and walked home to put ice on it. Is it achilles tendonitis? I don't think so, but I'm not sure. It feels like it's the muscle. Anyway, better safe than sorry. I'll try again tomorrow. Maybe I should elliptical?