Pain below kneecap when running

You might want to go to a real running store and have a knowledgeable person fit you for shoes. There is a lot to your feet and if you don't get the shoes right (or they are old) the pain will travel all the way up thru your back. Once upon a time I heard 300 miles on a pair of shoes is considered warn out, Even if they look brand new. My wife had the same problem.

It might be your stride. I had the same issue and I went to a physical therapist who was also a runner. He filmed me running and showed me that I would put my leg out in front of me consistently and showed where the stresses would be on my knees. He had me change my stride to come down under my hips instead of in front and push off behind me. Does your knee hurt when you walk/hike ? That could indicate that your body position is different between running and walking.

could be a patellar tracking problem which can be fixed. I've dealt with this quite a bit, including surgery on both knees. I can hear my orthopedic surgeon in my head - he would tell you to wear a cho-pat knee strap or brace to help with tracking, strength train the muscles in your legs (tracking issues often start with muscle imbalances), and apply Australian Dream cream (can get it at walmart). Also, definitely get professionally fit for running shoes at a good running store. That makes a huge difference too!

My humble suggestions:
1 Warn up THEN stretch then run. I know, sounds simple, but made a difference on my shins.
2 Go to sports store, have your stride examined. Make sure your shoes is the right fit for the way you run.
3. Invest in a brace.
3 Strength train more. Particularly your legs. I could give you a 3 hour lecture on the importance of strength training when running and how it minimizes the impact to your muscles.
4. And lastly (prepare to roll your eyes), yoga. Keeps everything flexible. There are specific DVDs (and where I live classes) for runners if you don’t want to completely turn into a yogi, but give it a shot.

Whatever you do, don’t ignore your body.
Best of luck!

Directly under or mostly to the outside of the patella and a bit under? If the latter, might look into IT band stretching and foam rolling the IT band and attachments. Although the other suggestions are good also, since IT band issues are usually a symptom of something else, such as a muscle imbalance, a stride problem, or shoe issues.