Leg cramping when i start to walk morning 1km.after that i can't walk.it happens only to my right leg and i couldn't move further if i didn't take rest?

Couple concerns: If you were older, i might wonder about decreased blood vessel flow called intermittent claudication, but would also consider lumbar stenosis or a nerve root compression. You could possess some congenital problem affecting arteries or nerves. This issue should be addressed by your doctor asap, as there could be a large risk regarding your afflicted limb.