fat in the side of my knee with pain. Pain constantly, shopping (walking on concete) hurts.  Going up and down stairs my knee does lock or it feels like it is going to bend backwards.  Driving hurts my knee - pushing on the pedals, of course, especially the gas for a long time.  I had an MRI was told it was fat  I cannot exercise it away due to the pain.  Treadmills hurt - what can I do?