@bprather
I have spine issues and had cervical and lumbar surgeries/fusions due to spinal stenosis, degenerative disc disease, myelopathy spinal cord compression injury, small fiber neuropathy, etc.

Based upon your symptoms and my personal experience (also have a teen son with migraines with aura and Reynauds) my suggestions include:

1. See an orthopedic spine specialist to evaluate your symptoms, reflexes, gait, arm/leg strength, get updated MRIs of cervical and lumbar spine (may need MRI of both hips, too, to check joints and soft tissues/inflammation and this would be an orthopedic hip specialist). When my spinal cord and nerve roots were compressed in my neck, it caused daily headaches, neck/shoulder pain, tinnitus, hearing loss, arm/hand weakness and numbness, bladder control issues, walking/balance issues, etc. with lumbar spine compression, I had low back, buttock, hip, leg and foot pain/weakness and numbness. My EMG would show normal and at times radiculopathy. EMG alone may miss spine compression per my spine specialist so EMG alone is not enough to diagnose spine issues. I was also told I was born with a congenital narrow spinal canal which makes my symptoms more significant than normal for others. Your bowel issues and vision could be tied to your spine/spinal cord/nerve compression. You may want to rule out degenerative cervical myelopathy (I have this and now have some permanent spinal cord injury due to delayed diagnosis…took me 4 surgeons over 4 years to get a proper diagnosis).
2. Have a ENT/immunologist evaluate your swollen lymph node in throat to see if they recommend biopsy.

@bprather
Another suggestion is to have your neurologist evaluate your migraines, do a small fiber neuropathy skin punch biopsy to check nerve damage that affects skin sensations causing itching/burning/temperature issues. They should also consider a MRI of brain to rule out anything causing migraines and vision issues. My son was told by his neurologist to take magnesium and omega 3 supplements which have helped reduce his migraines with aura. The minute he gets aura, he needs to take Motrin or Tylenol before pain hits to prevent painful migraines that cause him to vomit. This helps prevent the worsening of his migraines when they start. Drinking a lot of water with electrolytes also helps him with POTS blood pressure drops. He has a heart defect and gets light headed when he stands up plus Reynauds blood vessel spasming. We use the LMNT electrolytes brand and it is good. You need to drink at least 50% of your body weight in ounces of water with electrolytes to ensure proper hydration. This helps with headaches and blood pressure.