How pain works, why you have both back and leg pain, and what makes chronic pain different — the science explained simply.
When you understand why you hurt, the purpose of each treatment begins to make sense.
What You'll Learn
- How pain works (the three components: body, emotions, and thoughts)
- The two types of pain: nociceptive pain and neuropathic pain
- What happens when a nerve is compressed
- Why you have both back pain and leg pain
- Why walking makes it worse (intermittent claudication)
- What chronic pain is and how it develops
- Common misconceptions about pain
Pain is a warning signal from your body.
Your nerves send electrical signals to your brain to say, "There's a problem here!"
A problem anywhere along this pathway can change how you feel pain.
Research has shown that pain has three components:
| Component | What It Means | Example |
|---|---|---|
| Sensation | The physical pain signal itself | "It throbs," "It tingles" |
| Emotion | The unpleasant feelings that come with pain | Anxiety, frustration, feeling down |
| Cognition (thought) | How you interpret and think about your pain | "What if it never gets better?" "Moving will make it worse" |
So how strongly you feel pain depends on more than your physical condition. Your emotions and how you think about the pain also play a part.
An important point: This does not mean the pain is "all in your head." All three components are real processes in your brain. That is why managing how you relate to your pain is a proper part of treatment, alongside treating the body.
There are two main types of pain. Each responds to different medications, so it helps to know which you have.
This is the pain you feel when tissue in your body is injured or inflamed. Nociceptive pain is a warning signal, like the pain you feel when you touch something sharp or hot and pull your hand away.
| Feature | Details |
|---|---|
| What does it feel like? | Throbbing, aching, a deep or heavy pain |
| Causes | Fractures, joint inflammation, muscle strain, etc. |
| Effective medications | Anti-inflammatory painkillers (NSAIDs) such as ibuprofen or naproxen |
| Key characteristic | A "warning" pain that protects your body |
This is pain caused by damage or malfunction in the nerve itself.
| Feature | Details |
|---|---|
| What does it feel like? | Burning, electric shock-like, shooting, stinging |
| Accompanying symptoms | Numbness, reduced sensation, pain from light touch |
| Effective medications | Gabapentinoids (e.g., pregabalin, mirogabalin), duloxetine (ordinary painkillers are often ineffective) |
| Key characteristic | Pain from a nerve "malfunction" |
In lumbar spinal stenosis, both types of pain often occur together.
This is why you may need several different medications: Anti-inflammatory drugs treat your back pain, and nerve-specific medications treat leg numbness and pain: different types of pain need different medications. It may feel like a lot of pills, but each one targets a different type of pain.
Your nerves are like electrical wires running throughout your body.
They carry commands from the brain to the body, and sensations from the body back to the brain.
A compressed nerve is like a squeezed electrical wire. When its signals are disrupted, these symptoms can occur:
| Symptom | What Is Happening |
|---|---|
| Pain | The nerve is sending a "there's a problem!" signal |
| Numbness | Sensory signals are not being transmitted properly |
| Reduced sensation | You cannot feel touch as well as normal |
| Muscle weakness | The "move" command is not reaching your muscles properly |
When there is a problem with the lumbar spine itself (the bones, discs, joints, or muscles), you feel pain in your lower back.
This is pain coming directly from the site of the problem.
So why does your leg hurt or feel numb, even though the problem is in your back?
The nerves in your lower back travel down into your legs.
So:
The nerve is being compressed in your lower back, but the symptoms appear in your leg.
This is called radiating pain or referred pain.
| Compressed Nerve | Where Symptoms Typically Appear |
|---|---|
| L4 nerve root | Front of the thigh, inner side of the knee |
| L5 nerve root | Outer thigh, outer shin, top of the foot, big toe |
| S1 nerve root | Calf, sole of the foot, little toe side |
Your doctor can often determine which nerve is being compressed based on where you feel your symptoms.
The most typical symptom of spinal stenosis is intermittent claudication.
Intermittent claudication means: While walking, your legs become painful or numb, and you have to stop. After a short rest, especially if you lean forward, the symptoms ease and you can walk again. This cycle repeats over and over.
When you stand and walk, your lower back naturally arches backward.
When your back arches, the ligamentum flavum buckles inward, making the spinal canal even narrower.
This increases pressure on the nerves and brings on your symptoms.
When the body extends, the nerves are compressed and sciatica appears. When leaning forward, the compression is relieved and the pain subsides.
When you lean forward, your lower back rounds.
When your back rounds, the ligamentum flavum is stretched thin, and the spinal canal opens up.
This reduces pressure on the nerves, and you feel better.
That is why:
All of these positions involve leaning forward, which widens the spinal canal.
Normally, pain is a "warning signal." Once the problem is resolved, the pain should go away.
When pain lasts longer than three months, it can develop into a condition called chronic pain. Studies show that roughly 15% of the general population lives with chronic pain, and among those aged 75 and older, this rises to about 37%. Chronic pain becomes more common with age.
In chronic pain, the nervous system itself undergoes gradual changes.
An important point: Chronic pain is not "imaginary," and it has nothing to do with "not being tough enough." The nervous system itself has physically changed. That is why you should treat pain properly at an early stage. Some people refuse painkillers because they worry the medication will stop working when they "really need it," or because of side effects. Sometimes pain goes away on its own. But in conditions like lumbar spinal stenosis where pain persists, putting up with it can let the nerves become more and more sensitive until the pain is truly unbearable. And once chronic pain is established, it is much harder to treat.
Your body has a built-in mechanism for suppressing pain.
The brainstem sends chemical messengers, serotonin and norepinephrine, down to the spinal cord, where they act as a brake on pain signals.
When chronic pain persists, this braking system can weaken or even start amplifying pain instead.
How this relates to your medications: Drugs like duloxetine (Cymbalta), tramadol, and neurotropin work by strengthening this "natural braking system." They work differently from ordinary painkillers, so they can help pain that does not respond to standard pain medications.
Chronic pain often traps people in a vicious cycle.
In older adults, age-related changes make this cycle worse.
| Contributing Factor | Impact |
|---|---|
| Muscle loss (sarcopenia) | Less support for your body, more pain |
| Balance problems | Higher risk of falls |
| Osteoporosis | Higher risk of fractures |
| Reduced appetite | Poor nutrition slows recovery |
The goal of treatment: Treatment aims to break this vicious cycle.
Do any of these mistaken beliefs shape how you think about your pain?
| Common Misconception | The Reality |
|---|---|
| "Something must be damaged for there to be pain" | Pain can occur even without tissue damage |
| "The abnormalities on my X-ray or MRI are causing my pain" | Imaging findings and pain often do not match |
| "Moving is dangerous; rest is best" | Appropriate activity helps recovery |
| "If I can tolerate the pain, I should just leave it alone" | Even mild pain can become chronic if left untreated |
| "Painkillers are bad for your body" | Used properly, they are an essential tool for preventing the pain cycle |
Painkillers are like a fire extinguisher: A fire extinguisher can put out a small fire, but not a blaze that is out of control. Pain works the same way, so catch it early. When you feel pain, your painkiller works best if you take it within 30 minutes instead of trying to tough it out.
Once you know how pain works, the purpose of each treatment is easier to see.
| Treatment | What It Does | Which Type of Pain? |
|---|---|---|
| Anti-inflammatory drugs (NSAIDs) | Reduce inflammation and decrease pain signals | Mainly nociceptive pain |
| Nerve medications (e.g., pregabalin) | Calm abnormal nerve excitability | Neuropathic pain |
| Descending inhibition boosters (e.g., duloxetine) | Strengthen the brain's pain-suppression pathway to the spinal cord | Chronic pain, neuropathic pain |
| Nerve block injections | Temporarily stop signals in a specific nerve | Both types |
| Surgery (decompression) | Physically remove the pressure on the nerve | Pain caused by compression |
| Spinal cord stimulation (SCS) | Deliver electrical stimulation to the spinal cord, making it harder for pain signals to reach the brain | Neuropathic pain, chronic pain |
Each treatment works at a different point along the pain pathway.
| Key Point | Details |
|---|---|
| Pain has three components | Sensation, emotion, and thought all influence how much pain you feel |
| Two types of pain | Nociceptive (inflammatory) and neuropathic (nerve malfunction) |
| Leg symptoms | When nerves are compressed in the lower back, symptoms appear in the legs |
| Intermittent claudication | Walking narrows the spinal canal, causing symptoms; leaning forward brings relief |
| Chronic pain | The nervous system itself changes, leading to a vicious cycle |
| Early treatment matters | Addressing pain early is the key to preventing it from becoming chronic |
| Targeted medications | Different types of pain require different medications |
Tests and Diagnosis: how the cause of your pain is investigated
Treatment Overview: treatment options matched to your type of pain
Medications: how different medications target different types of pain
Consider asking these questions at your next appointment:
"Is my pain nociceptive, neuropathic, or both?"
"Based on my leg symptoms, which nerve do you think is being compressed?"
"Has my pain progressed to a chronic stage?"
"Am I at risk for a pain vicious cycle? What should I watch out for?"
"Given the current state of my pain, which treatments are most appropriate?"
Tip: Drawing a picture of where your pain and numbness occur and showing it to your doctor can help pinpoint which nerve is compressed. Also, descriptions like "burning," "electric shock-like," or "tingling" are signs of neuropathic pain. Describing the quality of your pain, not just where it is, helps with diagnosis.
This page provides medically accurate information, but it is not a substitute for professional medical advice. Please consult your doctor for diagnosis and treatment tailored to your individual situation.