Hi. I m a 35 year old female. I eat well and exercise often (swimming), and am generally in good health. I ve been having a pulsating sensation on the right side of my left knee for a few days. It doesn t hurt. My legs feel tired. It feels almost like a muscle spasm that comes in waves over and over again. It s as if I can feel the blood pumping through my veins, at my knee. My LDL was removed on both knees as a result of a car accident injury in 1995. I have Rheumatoid Arthritis (RA) and Fibromyalgia (FMS), however I have been able to prevent flareups through exercise, diet (Juice Plus), rest, and medication prescribed by rheumatologist . My question is, is this pulsating feeling something to be concerned about, or is it another symptom of RA/FMS?