Headache and nausea do not mean that it is cervical spondylosis, but cervical spondylosis can cause headache and nausea, for example, the common vertebral artery cervical spondylosis and sympathetic cervical spondylosis can lead to insufficient blood supply to the brain, or the excitation of sympathetic nerves causes stimulation reflexes, stimulates the vomiting center or causes insufficient blood supply to the brain leading to headache. There is also stimulation of the greater occipital nerve, the peripheral vagus nerve, and the sinus, which can all cause headaches. Muscle pulling can also cause pain behind the occiput or at the top of the head, but whether nausea and headache are caused by cervical spondylosis or not requires a specific examination at an outpatient clinic for a clear diagnosis. If spinal instability stimulates the greater occipital nerve causing pain, it is usually in the posterior occipital area, the top of the occipital area or even in the temporal area, which causes pain because of the blood supply. Therefore, if you normally have headaches and nausea suddenly caused by discomfort in the neck, it is best to go to an outpatient clinic for an examination.