What Causes Right Hand Tremor After Shoulder Surgery?

Hi, I had shoulder surgery (rotator cuff repair on right hand) 2 months ago and a few days after the surgery I started shaking on the right hand. This is still going on even though I am having therapy. My MD had me do a MRI scan of the cervical spine to rule out pathology. The findings were limited due to the motion secondary to an uncontrollable temor. The report indicated "there are mild degerative changes within the mid to lower cervial spine. C4 - C5, there is a mild diffuse disc bulge which causes mild bilateral neural foraminal narrowing, right side greater than left. C6-C-7, there is a mild diffuse disc buldge with a small broad superimposed right neural foraminal disc protrusion. This causes mild right neural foraminal narrowing". My current neurologist could not find the cause of my constast shaking.