strange soreness in calf

Lately, I have been having a strange soreness in my calf. It does not feel like it is in the gastroc (upper part of calf). It actually feels like it is the soleus. I have had problems with achilles tendinitis in the same leg but this is not the same. I actually have been having no problems with the achilles as of late. Anyone know what this might be? It feels a little like a muscle pull. It shows up the next day after a run and is gone in 2 days or so. Its kind of baffling me. I havent heard of any over use injuries like this. What do you think.