That’s a pretty normal reaction. Have you tried using an ice pack on the area? That works to reduce the swelling. Are you able to take Tylenol? This will go away in a day or so.

Because I lost all of my immunity with my stem cell transplant, I’ve had 29 vaccines in the course of a year, not including my covid and flu shots. So this reaction to most any vaccine is normal. Hah you should have seen my arms. Looked like someone pummeled me with baseball bats. But you really don’t want to get shingles if it can be prevented with the vaccine. So hang in there, your arm will fell better soon.
Try the ice pack.