Causes of headache and tremors are stress, anxiety and panic attacks,too much consumption of caffeine or
alcohol,low blood sugar(hypoglycemia),autoimmune disease like multiple sclerosis,thyroid disorders,cerebellar dysfunction and liver disease.
Pls check out your emotional state and coffee or alcohol consumption.Also get your blood sugar,thyroid hormones and liver function tests evaluated.If deranged,then pls consult a physician.
Hope it helps.