Not sue how ive done this but it may have been lack of exercise and plenty diuretics like beer coffee n chocky.
If I kneel on my shins with tops of feet flat to the floor I get an acute pain/tearing sensation starting at the outer tip of my big toe continuing across the top of my foot to the crease with my ankle.
I first noticed it pointing my toe to put my leg into my trousers or foot into welly.
Ive had it before it went away after a week say, I seem to remember purposefully stretching it through the pain to makes sure it would not shorten and retain flexibility, and cleaning my diet up with plenty water. Now googling tendinitis it says don't stretch.
So im not really sure what it is or how to deal with it best. Im gonna give it another week with a clean diet if it don't clear up see the dock.