People will always debate how often, far and the speeds you should run. However, whatever may be comfortable for you, may not be the same for anyone else.
I used to be able to run for 20 mins before literally, the pains in my shins and hips was too intense to go on. Research, and a few changes, and I went from 20 minutes to three hours without any strain being put on my body.
Since then I've continued to run a minimum of 20 kilometres a day and often way more on the weekends. Quite often during the week I run to work, from work home and at lunchtime. So, not only do I run everyday, but I often run multiple times per day.
Because I create movement without relying on power and force, I don't overwork my body. I never wake up with any tension or stiffness as a result and I truly believe you should run a certain amount a times per week because a magazine or coach told you, because of how fit you are, but it should be dependent on your efficiency of movement. People long before us (up to two million years ago, and since) had always run long distances, and we still harbour that ability. So, if you feel stiff after running, maybe think 'why' instead of coming to the conclusion of training frequency.