Over the last week I've developed a pain in my left knee. I can only imagine it's through karate or the gym but I spose it could've been caused by many things as I don't remember a specific event prior to the pain. It seems to be getting worse and is currently covered in Voltarol Gel and supported in a tube sock. Moving my leg in a natural forward back motion is no problem but the slightest movement to the side and I'm in trouble. Any thoughts?