Hello! You should know that usually the most common side effect of the flu shot is a reaction at the injection site, which is typically on the upper arm. After the shot is administered, you may have soreness, redness, warmth, and in some cases, slight swelling. These effects usually last less than two days. To help reduce discomfort, try taking some ibuprofen before getting your shot. But in your case two weeks after the shot, having these symptoms is unusually so I think you need a physical examination specially for muscle weakness by a neurologist to exclude a pathology. I hope my answer help you. Let me know if I can assist you further. I wish you a quick recovery. Regards, Dr. Monika Dede