Talk to General Physician on Twitching Sensations

A month ago I started having strange twitching sensations in different parts of my body,sometimes a finger,arm body radiated everything went normal,after a week it happened again my doctor recommended me a thyroid function test and an electrolytes test,both tests were doctor then advised me to take vitamin B12 symptoms reduced a lot but for a few days I have a strained neck and the skin of my scalp has gotten really sensitive.A light tug at my hair or slight scratching leads to itching and a really weird sensation.I have a slight headache too. A few days ago I was constipated but now that is fine. is something seriously wrong with me? can someone please help. thanks :)