An aching and sore arm is one of the most common side effects after getting the coronavirus jab.
With millions lining up to get their vaccines in a bid to stop Covid-19, many may wake up with a tender muscle the next day.
But one trick going viral on social media can help prevent you getting a sore arm after being vaccinated - and experts say it works.
People on Tik Tok have been swinging their arm around like a windmill shortly after the jab, like they are swimming backwards.
One user demonstrated the movement, writing: “This sh*t better work so my arm doesn’t hurt tomorrow”.
Dr Peter Chin-Hong, an infectious disease specialist and professor of medicine at University of California San Francisco, says the trick does actually work.
He told local news site SFGATE : "It actually does make sense to me as an infectious disease doctor. Basically, what they’re doing is increasing the blood supply to the arm that’s vaccinated.”
He added: “It remains local, so the first thing your immune system is going to say is, ‘Hey, there’s this foreign invader in here’.
“It’s going to start being trained, which is a good thing, which is what you want. So that inflammation happens at the muscle area.”
One of the most common side effects from the Covid-19 is 'having a painful, heavy feeling and tenderness in the arm where you had your injection', according to NHS Scotland.
However, this aching pain is just a sign that the vaccine is working to trigger the immune system.
When you are vaccinated, the arm muscle slowly releases it, with your body sending white blood cells to attack the foreign invader.
This can often lead to inflammation - but moving your arm around can help blood to flow to that area quicker.
The pain only lasts a few days and experts advise moving your arm only after the 15-minute allergic reaction waiting period is over.
