I had some good runs up to 1/11, then took my standard day-off to recuperate. About mid-day through the recuperation day, my left side started aching, and by the end of the day, was in sharp pain with every deep breath.
So, after some doctor consultation, chest x-rays, blood work, and overall lack of diagnosis, I consulted the Madman once again. He pointed me towards some great articles on running 'stitches', which led me to my old Gray's anatomy text. It looks like I have damaged a ligament, cartilage or tendon around my splenic flexure (under the left ribcage), which hurts like hell with every big bounce on the treadmill and precludes any semblance of deep breathing.
This bodes poorly for miles this week, which is unfortunate as I spent some of the weekend re-doing the home gym area with my wife (it looks GOOOOOD). Luckily, I had clocked 27+ miles before the injury, so if I can take a week or so off to let this heal, I can still hit my goal of 50 for the month. I may still end up bald-as-a-cueball at the end of this month if the alternative is damaging something important, as I can always grow hair back but this thing cannot be rushed. Its going to be 'hello dumbells' for me and some other big muscle work while this thing heals.