Hi, Thank you for your question. These jerks are called tremors and these tremors could be associated with fatigue, stress, anxiety or a form of panic attack. Other possible causes of tremors could be overactive thyroid, Parkinsonism disease, certain medications, alkalosis, and low blood sugar. Sometimes previous injury may cause pinched nerve and may be a reason of tremor but this possibility remains low. Therefore, it is quite essential to thoroughly assess the all possibilities here with the help of a doctor. Hope this helps.
Try taking GABA supplements!
My husband also sleeps with a c-pap machine and has the leg jerking. He was diagnosed with RLS...restless leg syndrome. Might be worth checking into. There's medication for it.