What caused sudden heaviness in my arms what caused sudden stiffness of my neck?

It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. Regular aerobic exercise is likely to be helpful. It would be prudent to see a doctor. Wish you good health!

I equate the sensation of heaviness in arms with weakness of the muscles. A pinched nerve in the neck wouldn't affect both arms simultaneously. How long do symptoms last? Are there other accompanying symptoms like lightheadedness, nausea,sweats,chest discomfort,generalized weakness,palpitations?. Hypoglycemia, electrolyte imbalance, magnesium or calcium levels would be some things to check for