Got it. I don't have any pain or dragging. It is starting to happen every day now; my head will also jerk backward when I am resting. I am also buzzing/vibrating inside. Yuck.
No, what you are describing are myoclonic jerks a form of movement disorder seen alone and also within other neurological diseases, of which MS is just one.
Spasticity is caused by a higher resting tone in a group of muscles which increases with movement (increasing more the faster the attempt to move) In it's severe form the spastic muscles actually cause a body part to bend or twist and can be very painful. In it's mild form which I have in my right hip extensors, the spasticity of the extensors want my leg to stay straight and the msucles resist my attempts to swing the right leg forward as I walk. So the pulling of the spastic extensors makes it feel like I have a 20# weight on my R ankle to drag froward as I walk.
Spasticity is often related to hyperactive reflexes, so minor stimulations to the tendon will make the reflex "jerk" happen. That's the only way that "jerks" are related to spasticity.
Quix
Yes, you are correct. Twitching or jerking movements.