A sore, aching arm with mild redness or swelling — or even a small hard lump you can feel — is a very common reaction. It's a normal sign that your body is mounting an immune response to the vaccine, and it usually settles within a few days.
How to ease it
- Cold compress: apply a clean cold cloth or a wrapped ice pack to the site for a few minutes to reduce swelling and soreness. Don't put ice directly on the skin.
- Move the arm: gently move and use the arm as normal — it helps with stiffness, so don't keep it completely still for fear of pain.
- Painkiller: if the pain interferes with your day, you can take a painkiller such as paracetamol as directed. If you're unsure, ask a doctor or pharmacist before taking it.
When to see a doctor
Most arm soreness gets better on its own. See a doctor if:
- the redness or swelling keeps spreading, or you get a large hot, red, painful area;
- it hasn't improved after a few days, or it's getting worse;
- there's pus or signs of infection at the site;
- there are signs of a severe or allergic reaction such as persistent fever, difficulty breathing, swelling of the face or throat, or a body-wide rash — seek care immediately in that case.
If you're not sure whether it's normal, the safest move is to check with your doctor or the clinic where you were vaccinated.