Based on the details and MRI report you have cervical radiculopathy
L) side secondary to disc prolapse
.Occipitonuchal headache is due to disc itself with muscle spasm
You require muscle relaxants like tolperisone , along with short course of pain killers with neuralgic drug pregabantin which will alleviate your symptoms.
Meantime use cervical collar
, and avoid weight bearingConsult neurologist
Dr Sandhya Manorenj