I am woman, 140 lbs, 5 7, 50 years old and having knee pain. Some days its intense. When pain occurs (when relaxing)in waves then numbness like blood flow slowed or stopped. Yesterday It felt like my knee was bleeding from inside like a cooling feeling? I can t kneel on it at all. Could it be arthritis? A year ago when I bend by knees or climb stairs it sound like tiny bones crackling. I don t remember injuring it.