My husband complaining of pain tiredness of his right leg comes and goes it goes specially when he sleep and relax. what it could be?

Need testing: This is called claudication and it may mean a partial obstruction of the blood flow into the leg when walking. It will get worse if not treated. He needs to be checked soon. Worse condition can happen if the blood flow stops completely.

Many possibillies: and the most common cause fo the symptoms, restless leg syndrome is also the one that fits exactly the symptoms. It is a NOT SERIOUS disorder when the brains ability to damp down nerves/muscles is not as strong as their activity....hence restless leg/cramps/pain/spasm. Worse at night (less brain activity). Any anti-parkinson's medicine works on it. Muscle spasm meds often do too.