A cancer may press on the tissues around it or on a nerve.
Infection can set up a painful reactiondue to inflammation in the tissues.
Damage to tissues following surgery or radiotherapy may lead to pain. These are often a cause of pain, especially in the bones. Sometimes, pain can occur in places well away from the cancer which is causing it. This is because nerves may carry pain between totally different parts of the body. So pain caused by a tumour in the chest may be felt in the shoulder or arm.