Arm Pain After a Meningitis Shot: Causes, Remedies, and Legal Options Lets do my first B12 injection together This is something Ive been nervous about for a long time, but today I finally did itand it honestly wasnt bad at all. I used the Union Medico needle guide B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Flu Shot Side Effects: What's Normal and When to Call Your Doctor