Leg shakes when heel is raised. is this a kinetic tremor or clonus?

Depends: Tremors can develop later in life and usually have a rythym or speed you can measure and discuss with your doctor. Mild tremors occur in weakness and pain, and usually get worse (temporarily) with fatigue. Your "shakes" sound like a tremor, not clonus.

More likely clonus: A kinetic tremor refers to a tremor present during activity and usually signifies cerebellar dysfunction. If that were so then one would expect similar complaints from the corresponding arm. Clonus refers to an increase in tone in the affected limb causing rhythmic flexion and extension at the ankle although it can occur less commonly at the knee. A good h&p can sort out the difference.