Definitely seems to be neurological. The nerves do strange things to the body. Do you remember an injury? Or something you did that threw your neck or back out of whack? Years ago I started getting headaches, very unusual for me. Then my arm (left) felt like I was stuck in a live electric socket. This happened several times a day, for months. Felt like a bolt of electricity. I had an MRI. The first Dr who read the results showed concern that I possibly needed surgery. A second opinion from a different hospital and a neurosurgeon said This will subside, don't let anyone talk you into surgery. It took time but eventually the headaches and arm electric bolts went away. Something I did to my neck. That kind of injury can affect your nerves anywhere in the body. I didn't remember an injury. How long have you had these symptoms? I'm obviously not a Dr, but your kidney function looks pretty normal. Just a thought from my experience.

My kidney function has been steadily declining over time. A chronic condition and from what I understand it will not get better but could be stabilized.