Restless leg 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 during the early evening or later at night. The characteristic nighttime worsening of symptoms in people with restless legs syndrome frequency leads to insomnia. Restless leg syndrome usually begins slowly. Over time, the legs become more affected. Less frequently, restless leg syndrome can affect the arms.