Tightly holded my right leg! PLZ HELP?

It is probably a muscle spasm, im not sure why but try stretching regularly and if it persists ask a doctor. it could be a nerve ending that's acting funny, i have one in my shoulder and every once and a awhile my shoulder feels like ive been carrying some thing on it all day and it gets tight. so you should def get it checked out if it doesn't go away.