Sounds like you have a strained calf.  Everyone heals a little differently, and from my experience muscle strains usually take ~2 weeks to heal.  I say this because I've had this happen to my hamstring twice and calf once.

Keep stretching and massaging it regularly, not just before or after a run. And when you do run, make sure you do so only at a pace where you don't have any discomfort, otherwise the healing will drag on.

You should be fine by the time you have your race on the 24th.

Here is what I think is a pretty good rehab article.  Patience seems to be the name of the game with calf problems.  I had a good pull of a gastroc once and ended up taking 7 weeks off.  That worked, even if it was overkill.

http://www.thestick.net/Articles/Calf_%20Heart_%20Attack.htm

Len

Last October (08) while training for the Memphis half, I had the same thing happen.  Less than 1 mile into my run, I thought I had a severe cramp in my calf.  I rested, stretched, walked, everything.  After two weeks I went to a sports doc.  An MRI determined it was a minor calf tear.  He kept me on Ibuprofen, had me stop training for a couple weeks, then cross train on a bike.  After about 4 weeks I started back slow on soft surfaces.  Be patient.  Running on with an injured muscle will only make it worse. Overall it took me 6 weeks to feel comfortable again.  But it did heal completely.  I was able to run the half in December 08 and then the Nashville full in April 09.  Be patient.

Thanks for the article...I'm guessing this is my problem at the moment.  However, the pain I feel only occurs AFTER my run.  Just when all of the stiffness/soreness hits in the usual spots (the kind that is fairly expected after a long run), my left calf locks up making walking miserable for a day or so.  It goes away and is fine through the next run...until 30 minutes to an hour later when it returns.  It is deep in the muscle and is taking its sweet time to heal. 

I have been to a Chiropractor...not sure how I feel about those yet but he was highly recommended by my CrossFit trainer.  The deep tissue massage really felt great.  He also used The Stick and while I hated every minute of that (it does not feel good), that, too, seemed to help. Unfortunately, I can't afford to go back for those treatments as often as he feels is necessary.  My plan is to take a good week off and then ease back with some swimming/pool running for a week.  I am really close to the 18 week training window for my first Marathon so I need to get this healed up before ruining that plan.  If you find something that works, please share!

I'll be sending good vibes your way, too!  I did find this article and it seems to hit most of my issues (except I don't have bruising).  Do you have compression sleeves?  Those do seem to help me.  I'm going to rest, try a little rehab in the pool and hope to get out on the road again soon!

http://www.physioadvisor.com.au/9457050/calf-strain-soleus-lower-leg-injuries-calf-t.htm