There are plenty of people who are not overweight who have sleep apnea. Your doc was just adding confusing information. You can still have sleep apnea.

There are two kinds of sleep apnea. The most common is Obstructive Sleep Apnea. This is where tissue in the throat falls into the airway obstructing good breathing. This is often treated with a CPAP device. Sometimes, laser surgery can cause the tissue to tighten up.

The other kind is Central Sleep Apnea. This is where the brain, due to neurological injury or dysfunction, stops telling the diaphragm to pull a breath. It is very rare but can be devastating to those who suffer from it. There are not many ways to treat it successfully. Most sleep specialists are not very helpful with CSA.

My shaking would be as simple as a jerking arm to a whole body jerk. It would happen just as I was drifting off to sleep. I rarely experience this any more.