I'm 28, relatively thin, been running casually sometimes, and also got knee pain after a few months last time I got into running more seriously. I stopped for a while, did various strengthening exercises that I found on Youtube and most importantly adapted the to front-middle strike.
For this, I also got low drop (4mm) shoes, which made adapting the strike so so much easier.
The knee pain is now gone and I feel that my leg is in better shape--strength better distributed--because of the front strike.
I once went to a sports doctor about my knee pain. As I recall, he charged me $600 for an evaluation, and prescribed orthotics. The orthotics did not have any effect, despite my wearing them for years.
For this, I also got low drop (4mm) shoes, which made adapting the strike so so much easier.
The knee pain is now gone and I feel that my leg is in better shape--strength better distributed--because of the front strike.