Ernie, the B12 is probably a red herring. It probably didn t cause the problem you started with or the arm sensations. When you have the constellation of things that are bothering you, it is reasonable to look for a systemic problem. It sounds as though your doctor has done that and not really found a culprit. Often, the problem is not an illness but a lack of some of the things that we all need to stay healthy. Specifically ask yourself and of your doctor about, Exercise: Exercising every day for 20 minutes should be your goal. Is your body weight excessive. A little bit can go a long way if it is mostly in your belly where it affects sleep, joints, heart rhythm and when you re older, diabetes and heart disease. Abnormal sleep. Sleep disturbance is often present in people who are overweight, particularly those who snore. If you are very tired in the morning, sleep easily during the day and snore loudly, you may have sleep apnea. It is a common cause of abnormal heart rhythm requiring treatment.