Chronic pain does not go away by itself and can last the rest of someone’s life. Many conditions or diseases, such as arthritis, back pain (not the result of recent surgery), and cancer can cause chronic pain. In some cases, the cause of the pain is not known, and needs to be investigated by a doctor.
Chronic pain can be mild, moderate or severe, as can acute pain. Chronic pain can cause reduced mobility or depression, to name but two possible long-term effects.
There are many different types of painkillers that can be used to relieve both acute and chronic pain. The object of all of them is to return the body to a pain-free, or less painful state, and to improve the general functioning of the patient.
Symptoms of acute pain
(References: medicine.net; pain.about.com; patients.about.com; ncbi.nlm.nih.gov)