Sorry, this is a bit long, but this injury has me completely stumped. I was planning to run the USATF XC meet next month, and I've resigned myself to the fact that that probably won't happen now, but I'd still like to get healthy for outdoor track. Thanks in advance for your help.

Over the past year I've vamped up my training a bit. I did it "correctly," following the schedules of a personal coach, and built slowly over months and months of training. I had a successful fall, built up to around 70-80mpw and had little trouble with any injuries besides some shin splints that required little more attention than trying to run more on trails than roads. I took a week off over Thanksgiving and resumed training, built back up to 70-75mpw and was feeling pretty good.
Just before Christmas I got bronchitis, so I took 4 days off from running. When I started back I immediately noticed some calf pain, but I figured I was just tight from my days off. I ran 4 days of easy running, 3-8 miles, then did my first workout, which was about 2/3 of the originally planned one. I then moved back into the training that had been planned, but the calf pain didn't loosen up, and was slowly getting worse. Then over a weekend it started getting a lot worse, to the point that I had to cut an easy run to half distance. The next day I tried to do some mile repeats, and same thing, had to skip half of them and hobble home. Since then I've pretty much not been able to run. I was going out and just trying to run easy until it would hurt, but that time was shrinking, and when I only got through 15 minutes on Saturday, I decided it was time for some days off.
I've been to see a PT who's working on it, but so far, there doesn't seem to be much of anything that helps it feel better, even to his surprise. The most significant thing he noticed on his exam was that my anterior tibialis in that leg was markedly weaker than the other. The pain is mostly along the posterior calf at the soleus muscle-tendon junction, and it radiates along the medial tibia to my knee and ankle. When I start running the anterior tibialis starts hurting also and there will be a shooting, but not necessarily severe, pain that can go into the posterior thigh and down into the medial and lateral ankle. The calf muscles are tender and the pain worsens the moment I stop running, but it continues worsening too if I continue to run, to the point that it forces me to stop.
I'm doing the NSAIDs, icing, stretching, massage, and I've taken the last two days off. I tried biking tonight, which the PT thought would probably irritate it, but to my surprise, that didn't hurt it at all. He's been doing massage when I go in and there's a very noticeable knot about halfway down the medial side of the calf muscle that he's been working on. He also said that my ankle is unexplicably limited in its ROM. I also wonder now if the shin splints from this fall and this new pain aren't somehow related. (????)

Please help me figure out what is going on! If you've ever had symptoms like this, or have any suggestions for other treatments, I would love to hear them as I am so frustrated. The most baffling thing of course is that I was coming off of rest when it started hurting. The PT's diagnosis was posterior tibialis tendonitis as the main culprit with anterior tibialis and soleus irritation as a secondary result of compensation.
Thanks for your help!!
Danielle