Pain is an uncomfortable and unpleasant sensation – and emotional experience – that occurs when tissues in the body are damaged.

Pain is felt when particular nerves within the nervous system are stimulated by pressure such as that caused by:

• a tumour
• external things such as extreme heat or cold
• damage to surrounding tissue.

Your nervous system is made up of your brain, spinal cord, and a network of nerves that thread throughout your body. The brain is the control centre for your body.

Your brain uses the information it receives from nerves to coordinate your actions and reactions.

When a nerve is stimulated – by heat, cold, touch, or sound vibrations – it sends a message to your brain and you feel a sensation. Messages can also be sent in the opposite direction from your brain to any part of your body.

Acute pain

Acute pain is short-term and is caused by an injury such as a burn, cut, or sprain. Acute pain gets better as the injury heals. It is helpful because it draws attention to an injury. For example, if you sprain your ankle, the pain stops you from walking on the injury. This makes you rest and gives the sprain a chance to heal. Acute pain may also be caused by some cancer treatments; for example, a sore mouth due to chemotherapy. This pain normally goes away once the treatment is completed.

Chronic pain

Chronic pain persists over a long period of time and can be constant. It is often not relieved by resting. A person may need specialist treatment to control chronic pain.