What Causes Stiffness In Leg With Tremors?

my one leg has been very stiff now for the last 8 weeks, i was admitted into hospital with it because it worried me, sometimes it feels like i have to drag the leg to enable it to move, i did have tremours and leg cramps for a while but dont get those anymore, it affects my balance and co-ordination causing me to have several falls. I did do a couple of very strenuous walks about a week before it started. The hosital did check all of my reflexes and circulation and said everything was fine, they did 3 scans on my leg and hip and it didnt show anything, Can you please help?