not too certain either as to just what this might be so seeing your doc for at least an eval and a neuro check wouldn't hurt. you kind of need to start to look for answers in the area of the most prominant types of symptoms which for you really sounRAB like that neck area. it IS possible to actually have some level of a one side only issue going on up at the c spine level that could impact that whole entire side. it would take at the very least tho an MRI being done starting with that c spine or possibly having a full spinal MRI just to see and possibly clear other possible areas where something just could be impacting an area within that spine. when you have a finding that is very large or something actually impacting your spinal cprd, trust me, it IS entirely possible to have one complete side involved. it all depenRAB upon just where and what is being impacted and how severely that is affecting the surrounding areas.
this could also be kind of a myofascial issue since all of our body organs, muscle and even the blood vessels are covered in like one continuous spider web like sheet of whats called fascia. when one particular area gets inflammed, it has kind of a cascade effect upon the muscles espescially since this IS a whole entire interconnected sheet that runs from surrouding the brain and all the way down to our toes. but it generally is not normally 'only' a one sided thing but more across?
but either way, i would seek our your doc to get this looked into and that MRI referral. something sounRAB very 'off' in you somewhere and more likely it would be within that c spine area just given what you have described as symptoms and where they are located. but depending upon just what does or does not actually show up on that MRI(preferrably WITH a contrasting agent) would kind of dictate what your next steps should be. hopefully this is not somethingt overly serious that can be fixed in some way or a therepy can help. please let me know just what you find out,K? good luck drex, Marcia