Could the following cause left sided neck and head pain and arm pain . disc desiccation with mild broad-based posterior disc bulge. mild central canal stenosis with an ap canal diameter of 11 mm. slight flattening of anterior cord contour?

You describe cervical stenosis, and in view of narrowing of the canal, even a mild disc bulge will have a greater impact. Although your description does not mention focality other than your symptoms, this is not surprising, and does likely fit with pathology. Bothersome is "flattening" of spinal cord, which is consistent with compression. Get opinions from neurosurgery regarding all of this.

Yes, your symptoms can be (and most often are) associated with a herniated disc. This source of your problems can be confined with a thorough history and exam. Sounds like you already had an MRI. Options include physical therapy and possibly selective interventional pain management if pain is unmanageable. Surgery is the last option unless Neuro deficit or severe /persistent pain