Restless leg syndrome (RLS, restless legs syndrome) is a common cause of painful legs. The leg pain of restless leg syndrome typically eases with motion of the legs and becomes more noticeable at rest. Restless leg syndrome also features worsening of symptoms and leg pain during the early evening or later at night.
Restless leg syndrome is often abbreviated RLS; it has also been termed shaking leg syndrome. Nighttime involuntary jerking of the legs during sleep are also known as periodic leg/limb movement disorder.