Low back pain is one of the most common health complaints worldwide. For many people, it starts with a clear trigger, a sudden strain, lifting something heavy, or a disc-related injury. But what happens when the injury heals, yet the pain doesn’t go away?
This transition, where acute back pain becomes chronic back pain, is not random. It follows recognisable biological and neurological patterns, and understanding these causes is essential to stopping pain from becoming a long-term condition.
At Specialist Pain International, we frequently see patients frustrated by persistent back pain, especially when scans show “nothing serious.” The most common mistake is assuming ongoing pain means ongoing damage, when in reality, the cause is often more complex.
Let’s explore the key reasons why back pain becomes chronic and why these factors should never be ignored.
The Critical Shift: Acute Back Pain vs Chronic Back Pain
Understanding chronic back pain starts with a clear distinction.
Acute Back Pain
- Short-term pain lasting up to 3 months
- Directly related to tissue injury (muscle strain, disc injury, joint irritation)
- Improves as healing occurs
- Responds well to rest, physiotherapy, and short-term pain management
Chronic Back Pain
- Pain lasting longer than 3 months
- Persists beyond normal tissue healing time
- Often driven by changes in the nervous system, not ongoing damage
- Pain signals continue even when structures have healed
When back pain becomes chronic, it means the body’s pain alarm system is stuck in a heightened state.
Cause 1: Central Sensitisation (An Overactive Nervous System)
Central sensitisation is one of the most important and least understood causes of chronic back pain.
Think of the nervous system as a volume control for pain. With central sensitisation, that volume is turned up too high.
What happens in central sensitisation:
- Nerve rewiring: Persistent pain alters how the spinal cord and brain process signals
- Lower pain threshold: Nerves fire pain signals with minimal or no physical threat
- Pain without damage: Normal movements such as bending, sitting, or standing trigger pain even without injury
This is not psychological or imagined pain. It is a real, measurable neurobiological change and one of the main reasons why chronic back pain does not show up clearly on MRI or X-ray scans.
Treating central sensitisation requires specialised care that focuses on calming and retraining the nervous system, not just strengthening muscles.
Cause 2: Untreated Structural and Degenerative Spine Conditions
While nervous system changes often drive chronic pain, certain spinal conditions can contribute if left unaddressed.
Degenerative Disc Disease (DDD)
- Natural age-related disc changes
- Can cause inflammation, instability, or nerve irritation
- Persistent low-level irritation keeps pain signals active
Spinal Stenosis
- Narrowing of the spinal canal
- Compresses spinal nerves
- Often causes chronic pain when standing or walking
Spondylolisthesis
- One vertebra slips forward over another
- Leads to mechanical instability
- Causes muscle guarding and ongoing joint stress
Structural findings alone don’t explain pain severity, but when combined with nervous system sensitisation, they can prevent recovery.
Cause 3: Lifestyle, Emotional, and Fear-Based Factors
Chronic back pain is not purely physical. Behavioural and emotional factors play a powerful role in maintaining pain.
Fear-Avoidance Behaviour
- Fear of pain leads to reduced movement
- Muscles weaken and joints stiffen
- Movement becomes more painful, reinforcing fear
Poor Sleep
- Pain disrupts sleep quality
- Poor sleep lowers pain tolerance
- Creates a self-perpetuating pain cycle
Stress and Anxiety
- Increase muscle tension and pain sensitivity
- Keep the nervous system in a heightened state
- Slow down recovery from pain
These factors don’t cause pain, but they amplify and sustain it.
When to See a Pain Specialist for Back Pain
If your back pain has lasted three months or longer, it’s time to stop treating it as an injury and start managing it as a chronic condition.
You should see a pain specialist if:
- Pain has persisted for more than 3 months
- Fear of movement limits daily activities
- Pain feels worse than what scans suggest
- You rely on medication to function
- Repeated flare-ups keep returning
Dr. Nicholas Chua specialises in identifying the drivers of chronic back pain, particularly central sensitisation. Treatment focuses on addressing neurological, structural, and lifestyle contributors together, rather than offering temporary fixes.
The Bottom Line
- Chronic back pain is not simply an injury that hasn’t healed
- Nervous system changes play a central role
- Structural findings alone do not explain pain persistence
- Early specialist intervention reduces long-term disability
At Specialist Pain International, we focus on calming the nervous system, restoring safe movement, and addressing all factors that keep pain active, helping patients regain control of their lives.
