I believe it is truly important to understand the definition of the word "chronic" before defining anything further. The word "chronic" differentiates the disease, illness, or pain from anything "acute". Words like unending, persistent, unable to cure, etc. are associated with the word chronic due to the fact that most chronic diseases and pain have to cure or last for long periods of time.
THE SPOON THEORY
The term "spoons" was created by activist, Christine Miserandino in 2003 when she was trying to explain what having Lupus, a chronic illness, felt like to a friend. The metaphor is used to explain how people living with chronic illness and chronic pain ration their limited amounts of energy for daily tasks.
Daily tasks for those with chronic illnesses/pain is extremely difficult to manage in the beginning because of the factors your symptoms play in. Symptoms don't have a convenient time to play and counting"spoons" helps you plan your day....and even your life better.
The term "spoonie" describes someone who lives with a chronic illness/pain.
The U.S National Center for Health Statistics defines a chronic disease as a disease that persists for at least 3 months or longer.
"Chronic diseases are in contrast to those that are acute (abrupt, sharp, and brief) or subacute (within the interval between acute and chronic)"
Chronic illness can range anywhere from diabetes to autoimmune to arthritis to lupus to multiple sclerosis to even mental health illnesses. The list goes on!! You may even have chronic illness without a name, many live with chronic symptoms (such as thyroid disease, fatigue, aches, autoimmune issues etc.) and have yet to find or will find an umbrella term for it other than chronic illness!
Chronic pain can arise from a past injury, an illness, or unfortunately for some, there is no real cause to their pain to be found.