Calf knotting is miserable - I hate it. It ruins runs (forcing drop outs). Sympathies.
Your calf may not be the issue - for me it's all related to glutes (& sometimes hamstring) flexibility - & whether or not there's any "give" / available slack in the system.
Whatever it is , I hope it resolves quickly.
I've not had this issue so much since I started including glut stretches in my routine so you could well be right. I'll have to try harder. Hopefully pilates tomorrow will help as well.
Yes - Pilates will certainly help. Lack of "give" in the glute area can also cause achilles pain, though I doubt your (other leg's?) achilles was definitely caused by that.
Well, I'm on my bike today , so we're all rather .... crock? :-\ sigh.