The jerks you're describing as you try to fall asleep are usually hypnic jerks, a normal sleep reflex that gets stronger with exhaustion, stress and broken sleep, all common four days after a C-section while you're adjusting to night feeds. They aren't related to your anaesthesia, which would have left your system days ago.
Next Steps
Try to nap whenever your baby sleeps, keep the room calm before bed, and mention this to your obstetrician at your routine postpartum check so it's on record.
Health Tips
Get checked urgently if the jerks come with a severe headache, blurred vision, swelling, very high blood pressure readings, or any loss of awareness, since those need same-day review.