I had heart & blood pressure issues w/ ES. Mine were more evident when doing a hard cardio workout as my BP would drop instead of elevating then my heart would race crazily, I’d get totally breathless & feel like I was going to pass out. I also had heart palpitations. Those symptoms stopped for the most part after my styloids were shortened.
I had horrible occipital pain at the back of my head at the base of my skull. It took a year or more after my surgeries for it to stop but it finally went away.
I seriously think your arm symptoms could be TOS related so I’m really glad you’re getting a second opinion on that. Since the veins that get squashed w/ TOS are the lower part of the jugulars, it seems like it’s not uncommon for people w/ TOS to have other venous compression issues i.e. compression up in the neck or something like Nutcracker Syndrome w/ there is compression of the left renal vein which causes kidney/back pain. (Not suggesting you have that, just using it as an example).
Creaking & cracking in the neck isn’t too unusual w/ ES, but can coincide w/ cervical instability. I know you’ve said you’ve been tested, but did anyone evaluate you w/ an upright MRI & give you the following measurements which are used to evaluate instability: CXA Angle, Grabbs Oaks Score, & McReas Line.
Here’s a discussion about this with images from @Disabled_Inventor.