Understanding Pain

Pain is an inevitable part of life. We become accustomed to pain early in life from learning to walk and falling repeatedly, then learning to ride a bike and, again, falling repeatedly. This process never stops. A scraped knee is an obvious example of pain, but what about other types of pain, like a stomach ache, or that pain felt when bumping the “funny bone,” or even that pain that follows maximal intensity exercise where the chest is burning and muscles are seemingly screaming? If you’d like to understand more about pain and how it will influence your life, keep reading.

What is pain?

Pain in its most simple definition is an unpleasant response to a stimulus. Our nervous system contains checks and balances which help maintain homeostasis. The human body is full of receptors that sense things like temperature, or a mechanical change, or pressure. This signal is then sent up the spinal cord to the brain where it is interpreted and the body can respond accordingly. Our conscious brains have a limit to how much information can be processed at any given time and this will influence the interpretation of the signals being relayed to the brain. I’ve heard stories of operators in warzones being shot without realizing it because of the sensory overload their body is trying to process. So it all seems pretty straightforward, right-there’s a stimulus that is interpreted by the brain to be potentially harmful to which the body responds accordingly. Well, it turns out it’s not that simple. 

What influences pain?

Think about a sunburn that lasts a couple days with a little irritation and is only noticeable when direct pressure is applied over the burn. Now think about a sunburn from a long day at the beach that creates blisters and requires aloe vera to be applied every other hour just to handle the pain. Both are sunburns, but the pain response is very different. This factor affecting pain is the severity of damage to the tissue and the amount of tissue involved. Some less obvious factors influencing a pain response could be how someone copes with the pain, the length of time the pain is experienced, the environment, who it is experienced with, up-bringing and expectations, our predisposing factors, our level of fitness, genetics, the list can go on and on. A model that was taught to me in physical therapy school to conceptualize pain is called the biopsychosocial model of pain. This categorizes factors that will influence pain into three categories: 1. Our biology  2. Our psychology. 3. Our sociality. When dealing with pain, it is important to consider these factors and address areas of concern. Is there a history of knee pain which may predispose future knee pain if not fully addressed? Is there fear related to the pain? Is the pain being poorly managed without support from other people?

Categorizing Pain

Pain can be categorized in several ways, the most common ways being by time, severity, location, and type. Acute pain lasts minutes to weeks, subacute pain lasts weeks to months and chronic pain lasts months to years. Acute pain is usually viewed as an “appropriate” pain response and chronic pain is viewed as an “inappropriate” pain response. I understand acute pain to pain that has a known cause and which the body is able to resolve on an accepted timeline based on tissue heal times. Chronic pain is not as well understood and these people seem to have pain without a well defined cause or pain that persists beyond the normal expected healing time for that tissue. Subacute or chronic pain is not expected to get better on its own and may require help. Severity can be defined using a 0-10 scale based on the person’s experience with pain. Some tissue injuries (usually ligament or muscle) are given a grade from grade I to grade III where grade I is mild, grade III is a complete rupture. The location of pain is a starting point to understand the cause of the pain and an experienced physical therapist will be able to narrow down the location of injury. In some cases the pain is felt away from the location of injury as is the case with referred pain. This is one reason why an in depth examination is so important. The type of pain is understood using descriptive words such as: burning, sharp, radiating, aching, crushing, tingling, etc. This helps to understand the types of tissues involved, where burning or tingling is usually indicative of nerve injury. So, if a person has had pain at the outside of the right knee for 3 months described as an aching pain of 4/10 with no instability with testing and no reported bruising or swelling at the time of the injury, this may be a mild, subacute on chronic LCL sprain. If you have been diagnosed with an injury which was not explained well to you, this framework of understanding how pain is categorized should help. 

Is my pain normal?

People sometimes wonder if the pain they are experiencing is normal. Pain can be very unpredictable. In cases where pain becomes chronic in nature the nervous system can begin to develop different responses to stimuli. Hyperalgesia or allodynia are sometimes the result which is where something that is painful becomes abnormally painful or where there is pain to a stimulus that would normally not elicit pain. This type of response to pain can be very limiting for people and is another reason why pain should not be left unaddressed where it becomes chronic and more difficult and expensive to treat.

How long should my pain take to resolve?

The first time I had to wear a cast earlier on in life the thing I wanted to know most of all was when I could get the thing taken off. We have already discussed some of the complexities of pain and there can be a lot of variability to how long injuries can take to resolve. I will share a couple of frameworks that can be helpful in understanding how long something may take to heal. The most simple answer I tell some of my patients in the clinic is that however long a person has had the pain, that is how long they should expect to heal from their injury. Obviously, if someone comes in 1 day after a massive ankle sprain this framework makes no sense, but if someone comes in with 6 months of knee pain, then expecting 6 months of treatment may be at least a place to start. Another framework is based on 2 factors, the type of tissue and the severity of the injury. 

Minor Muscle, tendon, ligament tears can take 2-8 weeks to improve with more severe tears taking a year or more to fully heal. 

Broken bones will heal in 2-3 months depending on blood supply and the severity of the fracture. 

Cartilage heals based on blood supply, but is usually considered to heal very slowly, if at all. 

Nerves are highly variable with healing times, again, based on severity and location with times ranging from weeks to years. Some sources (1) suggest that healing nerves will grow at a rate of 1 mm/day. 

I have been dealing with pain, what can I do?

We all experience pain of varying degrees as part of the human experience. Pain is a complex problem and is not fully understood by modern science. Our healthcare system is not very efficient at treating chronic pain and often resorts to medicating and masking symptoms. It takes individualized care and careful management of pain to achieve meaningful and lasting results. Good treatment programs should address, not only the biology of the pain, but also the psychology and social aspects of pain which may include referring to other trusted professionals. Mountain Performance PT is committed to providing quality care aligned with the demand for a more individualized approach to pain management. 

1. Nerve surgery & nerve repair. Rebecca Ayers: Plastic, Reconstruction & Hand Surgeon. (n.d.). https://www.rebeccaayers.co.nz/procedures-and-information/hand-surgery/nerve-surgery-and-nerve-repair