That sounds an awful lot like low electrolytes to me. I woke with a kink in my neck one morning so bad I couldn’t turn my head to the right at all. Was like that all day long, i was getting worried. Then i remembered electrolytes, had a teaspoon of salt in a half liter bottle of water. Drank it slowly over about 10 minutes, and the kink faded away. I could actually feel the muscle relax. Since then i make sure to take a lot more salt.
I was taking so much salt, I was worried i might hurt myself not knowing what my sodium levels actually were. That same week I had a follow up at the VA. I asked my PC doc if i could get a full panel done, as I would like to see how my new way of eatingbwas effecting everything. I knew he would agree to that just to get me to shut up about curing my diabetes, and my cholesterol improvment WITHOUT meds, i refused to take them.
And everything in the labs on my blood and urine were in normal range. And all my electrolytes were smack dab in the middle of normal range.