There are multiple causes of laziness. Few of the major ones among our society is lack of sleep, stress or unhygienic habits which include wrong foods and inappropriate time table of daily life. One is also obesity related, which isn't very common among our population. There are also some side history that pertains to night habits, sexual practices, early morning fatiguing life style or wrong way of exercising. I could have guided you better if I had a more elaborated history and accompanied symptoms. Thank you for asking at Marham.