(specifically chapter 52 pages 461-462)
This is a text book that I used while in college and have referenced many times since. I will use the text to offer some further understanding to pain. The following has been re-typed exactly as it is in the text book.
"The most common patient complaint is pain; it is also the chief reason people take medication. Although pain is very common, much of it remains a mystery.
We all know what is meant by the term pain, but it is difficult to define. Pain or discomfort is the body's way of signaling that something is wrong. Pain is the sensation of distress, suffering, or discomfort elicited by a potentially harmful stimulus.
There are two categories of pain: acute and chronic.
Acute pain is the sensation that results from an injury or serious disorder. It is referred to as protective in that it serves as a warning and is often alleviated by time. Acute pain often responds to resting or favouring the involved body part, and it is usually possible to identify exactly what stimulus caused it.
Chronic pain is pain that continues beyond the initial phase of healing. It is difficult to identify an exact length of time that must pass before acute pain becomes chronic but pain that continues more than a few weeks is usually considered chronic. Chronic pain does not serve a purpose; it just exists. In some cases a definite objective cause cannot be documented. A group of associated symptoms surround chronic pain and the treatment must be aimed at alleviating these related symptoms. The treatment regimen for chronic pain differs from that for acute pain.
The term intractable pain refers to pain that is severe and constant or unrelenting. Usual nursing and medical procedures do not relieve this pain.
Location of Pain
Pain is often categorized in relation to the area of the body where it originates. The major categories are superficial, deep, and central pain.
Superficial pain originates in the skin or mucous membranes. The source usually can be located easily because there are many nerve endings in the affected structures. The patient often describes superficial pain as prickling, burning or dull.
Deep pain originates in the inner body structures. It may be manifested by vomiting, blood pressure changes, or weakness. The patient may have difficulty in pinpointing the exact location of deep pain, or it may be referred from one organ to another. The patient often describes deep pain as aching, shooting, grinding, or cramping.
Central pain is a complex mechanism, involving pain in the central nervous system itself. It may involve a combination of physical and psychological factors.