I am certainly no professional at this, but I have enough experience with knee pain after my knee surgery after running in high school, that I feel like I should be. Aside from physical therapy that is normally suggested after knee surgery or other injuries that can affect your running, there are a few techniques that I can think of to help with knee pain.
I would definitely make sure that you are stretching each and every day that you can, especially before you run. There is an ongoing debate over if you should be doing static or more active/plyometric-type stretching before and after running, but honestly I’ve done both and felt fine either way. I am actually more used to doing static stretching, because I feel like it allows you to stretch out individual parts of your arms and legs. A combination of both never hurts though. My physical therapy training also taught me to use a band to stretch out my legs to alleviate the tensions in my joints, which I posted an example of that I found on Google. Here is an article on active.com on combining plyometrics with dynamic stretching as a warm-up to check out: http://www.active.com/running/articles/combine-plyometrics-with-dynamic-stretching-for-the-ideal-pre-run-warm-up.
The next thing I would do is to make sure that you have the right kind of running shoe for the amount of training/running that you are doing. If you are training for a longer distance race, such as a 10k or half marathon, or even just doing a 5k, I would suggest that you buy a shoe that has plenty of support. A lot of running stores now offer you an option to run on a treadmill while they tape your running style to ensure that you have the right running shoe, depending on what type of runner you are (i.e.: I have had a tendency of over-pronation in the past and had to get specialized shoes/shoes that are more beneficial to fixing the problem). I have also gotten special inserts for my shoes for extra support to ensure that I didn’t injure myself. It also can allow for a little extra beating on your shoes. I would still suggest that you replace your running shoes every 6 to 8 months, depending on how much running and training you are doing.
Now that I have beaten having the right type of gear to death, let’s talk more about technique. I would suggest trying to find either a running path or a track that is padded, since some of them are rubberized and are not as harsh on your knees. If you do not have these options, I would suggest running on dirt paths or on the grass if you continue to have issues with your knees. One note that I would also like to add is to be careful about how much running you are doing on dirt/sand paths, because too much lateral movement can also be detrimental to your knees and this is why I had to get knee surgery in the first place (also, this was after 5 years of track running and 4 years of cross-country running). I have also heard that certain ways of running can be easier on your knees than others, so I would also try to look at your form to see how your foot is striking the ground when you run. Inserts and the right running shoes can help you a little with your form as well.
I would suggest icing your knees if the pain lasts a few days. If the pain is more prolonged and persistent, I would definitely suggest seeking out a doctor and/or physical therapist. There are certain issues that can’t be fixed by stretching and using the right running techniques alone. Happy Running everyone!
Two things I wanted to add to this segment that I forgot about until now are: 1) Alternating between running and strength training. So normally one day running and the next day strength training so you’re not putting as much pounding on your legs, and 2) Using a foam roller when you’re stretching out your legs, it can help to roll out some tension in your legs and hips, which can loosen the pain in your knees.