[danpat]

For running, this sounds very much like:

https://en.wikipedia.org/wiki/Iliotibial_band_syndrome

Non-specific knee ache leaving you crippled walking down stairs, and some other specific movements that cause the iliotibial band (on the outside of your knee) to rub over the bone/bursa. Super common running injury.

For me, the fix is - ice, stretching, instantly stop running if I feel a twinge, and, most importantly, ramp up mileage very very slowly (first week, 1 block, second week, 2 blocks, third week, ruin 3 blocks). Learning what it really means to "ramp up slowly" was the big challenge for me - it's always too tempting to go "hey, I used to be able to run 10mi easily, I'll just crank out an easy 5" - boom, limping for a week.

[mlhn]

I ran alot years back ago. Knee ache which made it impossible to run.

As you said, and what a nurse told me I needed stretching. That's helped against part of the ache, but for the running, I read the book born to run. They talk about using your calf muscle as a spring (sorry if this is the wrong words, I am not a native english speaker).

To do this you need to take short steps where you land your feet under you all the time so you don't put your heel in the ground. Very tough training to begin with, but it at least removed all my running problems.

Since I was a heelrunner I had to start over, since this is very tiring.