Hi
Welcome to the MedHelp forum!
The various reasons for myalgia or muscle ache are Dengue, viral flu, lupus, Lyme’s, malaria, polio, electrolyte disturbance especially low potassium (so serum electrolytes should be done), dehydration, fibromyalgia, multiple sclerosis, inflammation of muscles or myositis (hence CPK-MB should be done), high eosinophil counts, use of certain drugs like statins, and post viral fatigue syndrome.
I would suggest you get the blood levels of the following checked if they have not already been checked: potassium, calcium, sodium, magnesium, vitamin B complex, or vitamins B1, B3, or B6 and Vitamin D. Generally deficiencies of any of the above can cause muscle twitching and spasms in localized or generalized areas of the body. Get your kidney function, parathyroid gland function and adrenal function tests done because these affect the electrolyte balance in the body. Stress, alcohol, caffeine and fatigue all cause similar symptoms. Hence if you take alcohol or coffee then cut this down. Sleep at regular hours and see if it helps. Certain sleep disorders and peripheral nerve disorders due to diabetes or hypothyroidism can also be the cause.
Since I cannot examine you and know other related conditions you may be having, nor is a detailed history possible on net, I have listed the various possibilities that should be looked into. Do discuss this with your doctor and get yourself examined. Take care!