Do this now if you can afford it. Try to find one of the smaller stores that really focuses on runners and is staffed by avid runners. A good store will have a treadmill and cameras to be able to look at your stride and make recommendations on both your stride pattern as well as your shoes. It was a running store that helped me find the Saucony shoes that have helped my ankle issues go away. :)
You could maybe also be dealing with an imbalance of strength between your hamstring and quadriceps. When runners have joint issues this can be the culprit or at least a key contributor. Adding in a couple sessions a week of weight training that include movements like deadlifts, good mornings, and back squats can strengthen the posterior chain (https://en.wikipedia.org/wiki/Posterior_chain) and address those imbalances.