I know some of those symptoms very well. Can I ask about the strangling/choking sensation, is it like your throat swells up for 30 minutes or so? If so, I know what caused mine, it was looking from side to side whilst my head was looking down (in flexion), e.g. when flicking through a magazine. I had to avoid the movement in order to avoid the consequences.
With regard to your MRI, I can see some extra fluid above the brain, as many of us have. You don’t have blatant Chiari but you do have what are called, low-lying cerebellar tonsils, see the post below for further info:
Regarding your neck, I can see a loss of lordosis (the natural C curve of the neck) in the neck bones that are visible (down to C4). There’s also a measure of anterolisthesis between C3 and C4 neck bones (top bone more forwards than the bottom one). I have annotated it below.