I had same issues after being a dedicated (but not particularly fast) 10k runner for 30+ years- by the way, I'm 48. I had stopped running due to chronic knee pain until I discovered the Cho-Pat knee strap. Fortunately for my overall health I also discovered Spinning, the indoor cycling program and used that as an alternative to running to keep in shape. Spinning strengthened my quads, etc. without impact and the Cho-Pat strap provided almost immediate relief from the patella pain. I actually have gained quite a bit of muscle mass in my legs from Spinning regularly. Although I've cut back on the road miles, I still am able to run 2-3x weekly without pain (3-6 mile routes) and am now back to doing several local 10k runs and a team triathalon each season. In addition to the road miles, my weekly schedule continues to include Spinning classes and road biking. I no longer need the Cho-Pat for Spinning or cycling, only for running. I've actually forgotten it a couple of times on a run and after an initial twinge of the old "pain in the knee" I was able to settle in and complete the run, but I don't make a habit of running without my knee strap. As an aside, Spinning is a great cross-train for running, assuming you have a good club and Spinning instructors. In the winter or when it is too wet to run outside safely I also like the eliptical trainer which gives a high cardio, low impact workout similar to Spinning or outdoor cycling.
Here's a link to Cho-Pat info that you can cut and paste into your browser. I have no connection to the company other than telling you that this product worked as advertised for me. Ace (as in Ace bandage) makes a similar knee strap that is very comfortable as well but the Cho-Pat is the original.
or go to cho-pat.com and look under the products heading for "original knee strap"
hope this is helpful