Try two things--because you are having muscle spasms I think this might help. Apply mustard packs behind your ears, at the base head on the back of the neck and over the place where you are having muscle spasms. (look on line for recipes, essentially equal amounts of mustard powder and flour (coconut flour if you have it on hand but other is okay). Add enough water to make a pancake like consistency (if you have distilled or rain water all the better). Leave on for no more than 20 minutes. Rinse clean. This is helpful also. Make a new body spray- which is about 1 part vinegar to 3 parts water. (use distilled vinegar) if it stings add water. Spray all over. Hands, feet too after washing. Apply to wet or dry hair above the ear and nape of neck, in ears, nostrils and all over the face and body. It oxidizes toxins (metals stuck in the pores). It will make you feel cool as it works. (Vinegar and mustard together or alone is also effective as a foot bath--where toxins eventually end up and build up.)
I know you might dismiss this as unrelated and blame it on head trauma or a loud noise. Those problems can be simply the catalyst that moves heavy metal around from dormancy to high nerve signal areas. Tremor- I had in the beginning of this in my face and toes after dental work that I had a severe reaction to, then I lost my vision, then anxiety and then tinnitus. I lived above a loud base music playing neighbor and the sound made me ill. I had this happen another time riding in my son's car and getting a listen to his new speaker system- It made me sick and I had a nose bleed to go with it. This is because I had a mouth full of mercury that drained it and metals into my ears and sinuses all night, plus metal from surgeries in my hip that had to be removed due to failure of the part. Maybe you had braces and not a filling in your mouth. Maybe you had white dental fillings--those contain lead. Maybe you ate food that had a high content or had one too many shots that contained metal/mercury. This pushed your bodies tolerance over the edge--like your gut, your kidneys and liver can only handle so much. D3 for kidneys. B12 and B3 help. Dandelion root helps the liver. Once you start seeing some results, you will be able to feel and see mercury build up in your hands and feet because the veins swell, abnormally. Detox these too and your gut. Good Luck.