Why does my shoulder hurt after getting the COVID shot/booster?

The COVID-19 vaccine can spur some commonly known side effects. One of the most discussed side effects is a sore arm at the injection site.

You may have heard people who’ve been vaccinated against COVID-19 say their arm was out of commission for a day or two after their shot.

But why does your arm get sore after the COVID-19 vaccine? It’s a little more complicated than most people realize.

Common COVID-19 Vaccine Side Effects

Side effects from the COVID-19 vaccine are normal signs that your immune system is doing its job, according to the Centers for Disease Control and Prevention (CDC).

The side effects from the shot may impact your ability to do some activities, but they should last no more than a few days.

The most common side effects from the COVID-19 vaccine include:

  • Pain in the arm where you got the shot
  • Redness in the arm where you got the shot
  • Swelling in the arm where you got the shot
  • Tiredness
  • Headache
  • Muscle pain
  • Chills
  • Fever
  • Nausea

Side effects after your second shot may be more intense than after the first, but they are normal signs that your immune system is hard at work.

Why the COVID-19 Vaccine Can Cause a Sore Shoulder/Arm

The COVID-19 vaccine is an intramuscular injection, meaning it’s injected into the muscle. It’s recommended that it be injected into the deltoid muscle in the arm, the large muscle that gives the shoulder its range of motion.

There are a few reasons why this can cause arm soreness. The COVID-19 vaccines trick the body’s immune system to think it’s being invaded by the virus. As a result, your body sends white blood cells to fend off the “intruder.”

Why Does Soreness Last For a Few Days?

Your body’s process of reacting to the vaccine can take several days, which is why you may end up having arm soreness for that time. The pain from the inflammation caused by the shot itself also takes time to go away.

How to Treat a Sore Shoulder/Arm After Your Shot

If you have a sore arm after your COVID-19 vaccine, it should only last for a few days.1 If you’re uncomfortable, there are a few things you can do to help:

  • Move your arm after your shot. Using your arm and making a point to move it often after you’ve been vaccinated stimulates blood flow to the area and can help reduce soreness, according to Richard Watkins, MD, an infectious disease specialist and a professor of internal medicine at the Northeast Ohio Medical University.
  • Try a cool compress. Applying a clean, cool, wet washcloth over the area may help reduce soreness, Valdez says. “This may bring down the inflammation, much like when you ice your knees after exercise or injury,” she says.
  • Continue using your arm. It can be tough if you’re uncomfortable but stretching and continuing to use your arm can help minimize or reduce soreness.

If you are still experiencing a sore arm after a few days, we can help! Your Physical Therapist will be able to help you stretch and move your arm so you can feel better faster. The ultimate goal is getting your health back to normal and optimizing your levels of function.

We want to help you feel better soon! Visit our website here to learn more. Or easily book your appointment online now!

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