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Ouch! Why Does My Arm Hurt After a Shot?

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Medically Reviewed by UPMC

Why do shots hurt

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If you have ever received a vaccination, you know your arm may feel a bit sore for a few days after the shot.

The pain you are experiencing is usually soreness of the muscle where the injection was given. This pain also is a sign that your immune system is making antibodies in response to the viruses in the vaccine.

RELATED: The First Year: Downloadable Vaccination Schedule for Babies

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Pain After a Shot: Normal Site Reactions to Vaccines

According to the Centers for Disease Control and Prevention (CDC), in most cases vaccine side effects are minor and go away within a few days. Side effects vary according to vaccine type, such as flu, shingles, or pneumonia. Generally mild side effects of vaccines may include:

  • Pain, redness, tenderness, or swelling at injection site.
  • Fatigue.
  • Headache.
  • Itching at injection site.
  • Nausea.
  • Dizziness or fainting (most common in adolescents).

It is likely the combination vaccines — such as the diphtheria, tetanus, whooping cough (DTaP) — cause a greater local reaction and more of the “pain” you experience after the shot.

Can You Reduce Pain or Swelling After Vaccines?

If your arm hurts after a vaccine, there are some actions you can take:

  • Move your arm around after the vaccine. If you try to keep too still, it may hurt more.
  • Take a pain reliever for one or two days after receiving the vaccination to help with soreness and swelling.
  • Rotate a warm pack on and off the injection site.
  • If you’re concerned about the redness and swelling, outline the area with a marker. If it increases in size or does not decrease after a few days, call your doctor.
flu shot

RELATED: Why Should I Get A Flu Shot?

When Should I Seek Help for Injection-Site Pain?

Any injection site that continues to be problematic after 48 hours should be seen by your doctor immediately. Other symptoms that may warrant medical care:

  • High fever following a vaccination.
  • Signs of an allergic reaction, which can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat, or dizziness.

Concerned about pain, swelling, or soreness after your vaccine? Find a UPMC Urgent Care location near you.

Editor's Note: This article was originally published on , and was last reviewed on .

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