<s>[INST] Hello! I have a question last night I was going to bed and when I put my head on the pillow I got this very sharp pain in the right side of my head. It almost felt electric and my right arm went numb. I got very scared I have never experienced this before [/INST] Hello dear,I understand your concern.What was the duration of your symptoms in this episode?For single episode of sudden onset headache with numbness in  right arm ,the organic causes can be some seizure activity, a transient ischemic attack or a rare variety of  migraine.However,it needs to be observed, whether you have any such episode in future,before getting extensive investigations.A neurologist opinion may be sought,so that he may examine you and advise further.I hope it helped. </s>