Need to know what could be wrong when your legs feel like a rubberband is around the top of your legs?

This male is 47, now has a drooping left eyebrow and lid, weak on the left side and moves very slow when attempting to do anything physical. difficulty putting on clothes, unable to bring left leg up to put on sock, has had MRI nothing showing. loses balance, cannot stand on one foot. Legs are not showing signs of atrophy. no slurred speech. recently diagnosed with hypothyroid.