Thanks for your advices, lately i had the same problem where i run 10km / day for 2 weeks. I had old shoes and usually i walk 12km per day but i don't run. After 1 week i started to feel pain at my knee, i kept running anyway spartan mood. 1 week later i could barely walk , so i've stopped, now i slowly recover.
So you're right we should be progressive , have good shoes and rest enought :)