my left knee has been bothering me for 7-8 months now. i am in the army so they like to run alot. i do not remember an actual injury to it, all i know is that it started making popping and crackling sounds one day and the popping is painful, stairs walking running sitting standing bending ....pretty much everything bothers it, i have a hard time straightening out that leg it feels best slightly bent, i have tried several anti inflammatories and pain medicines nothing relieves the pain yet they have not done an mri, i have heard petellar tendinitis, ITBS, and runners knee for diagnosis, i have not ran on it in 6 months or done any real training, please help me find a diagnosis, the pain is getting worse NOT better.