metabolic conditions like hypothyroidism, hyperthyroidism related myopathy,
drugs like
salbutamol, alcohol consumption, amyotrophic lateral sclerosis, parenteral nutrition, hyperventilation etc. Your neurologist needs to differentiate from restless legs, intermittent claudicating and ischemic rest pain, muscle injury, lumbar nerve root entrapment, fibromyalgia and gullian barre syndrome.