After running in cold weather, my knees often ache and I want to know if anyone else experiences this and if they know what causes it. It typically starts right after I'm done running, or if the run is longer, it will start during the end of my run under both kneecaps. Both knees just ache and gradually the pain gets worse. I often run at work and then drive home and using my leg to brake & accelerate in the car is awful and quite painful, as it involves constant use & bending of the knee. The instant cure for this achiness is a hot shower. It works everytime and the aches are gone by the time I get out of the shower. Last year I had an unrelated injury which prompted an xray & MRI and both were normal - no arthritis or degenerative changes. Obviously it's not a huge problem since I know how to get rid of it and the cold weather will be gone again soon, but it drives me crazy not knowing the cause. Anyone else know what this could be or experience this?