The point being muscle knots are recognized areas of muscle that have clumps of protein adhesions which prevent smooth muscle operation when they grow to a certain point. Yet you can rarely see them. Most of the time you can't even feel them unless you press on them directly. It's another great metaphor for our lives. Sometimes a crippling issues is as simple as the casing around our tendons being too tight. Disclaimer, I'm not ruling out the stress fracture, I actually believe that I probably had both issues on top of each other.
The intricacies of a local deficiency, or any local issue, are such that you must be on your guard. Even cancer starts as one cell. So a little tendon, whose name I don't even know, has basically kept me from 20 miles a week for the last ten long weeks.
Sometimes I think about quitting competitive running so I don't have to deal with this any more, but the truth is, I have gotten the best out of myself and I don't know exactly what I would do otherwise.