Hi there. These involuntary jerking can be myoclonic jerks which can occur in head, neck, shoulders, arms, legs and torso. These can occur alone or in combination with seizure types or epileptic syndromes, absence epilepsy, myoclonic epilepsy, etc. Myoclonus is brief involuntary twitching of a muscle or a group of muscles. It is a medical sign suggestive of underlying nervus system disorders like multiple sclerosis, parkinson’s disease, alzheimer’s disease, serotonin toxicity, some forms of epilepsy. It may originate from lesions of cortex, sub cortex and spinal cord. you need to consult a neurologist for evaluation and investigations like electromyographyEMG and electroencephalography EEG. These should help you with diagnosis. You might be prescribed medications like anti convulsants depending on the type of epilepsy diagnosed. Hope this helps. Take care.
Needless to state, you require a neurological evaluation, preferably at a teaching hospital.
There are four tthings that could cause this problem.
(1) not so bad things
(2) bad things
(3) very bad things
(4) extremely bad things
Your problem could be as simple as a temporary infection or reaction to medication of as serious as a malignant brain tumor. Those symptoms are nothing to fool around with.