The SCM is innervated by the accessory nerve which is indeed one of the cranial nerves often irritated by ES. It’s possible that whatever position your elongated styloid &/or calcified stylohyoid ligament end up in when you’re lying down, there is pressure being placed on your accessory nerve & thus you get the jumpy muscle response. There is a chance this problem could go away after you have ES surgery. You would need to remember it has been a problem for many years so it would possibly take many months post op for your problem to fully disappear. Additionally, your heart issues could be caused by an irritated vagus nerve. There has been much forum discussion recently on the many body functions affected by the vagus nerve when it is over or under stimulated. Heart rate & blood pressure are for sure among those. The vagus nerve is almost always affected by ES in some form or fashion. I had low bp & heart palpitations which resulted in breathlessness & light-headedness when I exercised as part of my ES symptoms.
At some point, vanity needs to be put aside in deference to being able to live life normally & fully. As JustBreathe & BrooklynGirl noted, lip droop, tongue issues, first bite syndrome & the like can result from ES surgery but don’t always, & almost always when they do, the nerves heal & those problems go away some months after surgery. They are inconvenient but not life threatening & for the most part do not affect quality of life. Sorry if this sounds harsh, but I feel strongly on this point.