I wonder if your calcium/magnesium/phosphorus/potassium ratios are goofed up. Is the discomfort lower back or trapezius/lats? I don't know much about this stuff. Is the pain unilateral or bilateral. If you try the massage thingie on the muscles (avoiding the vertebral column) and get some relief, that would suggest a neuromuscular component. Then again, the ionic environment can mediate neural/electrophysiological muscular malfunctions. Of course, impingement of vertebrae on nerve trunks can cause pain. Maybe if you run the massager along your vertebral column and it intensifies the pain/ache/spasm, it would suggest, oh I dunno, anomalous intervertebral disc configs. I'm glad you eat a lot of bananas.
Wow, there's a deluge outside. They said the weather would be wet but this is really excessive. Gonna try to catch 40 winks now. Maybe a glass of milk with the banana would help. Have you ever used muscle relaxants? Wish I could be more helpful.
Lower back, down the glutes and into the back of thighs, more on left than right. Lots of bananas, usually with yogurt.
I hope you get some sleep. People in your time zone shouldn’t be up!