The Structures Involved

Most lower back pain comes from one (or a combination) of the following:

• Muscles
• Tendons
• Ligaments
• Nerves
• Discs
• Bony structures, including the facet joints of the vertebrae

Understanding which of these is involved — and why — is the first step toward effective treatment.

Age Matters More Than You Think

While anyone can experience lower back pain, certain causes become more or less likely depending on age:

• 20s and 30s: There’s a higher likelihood that pain is coming from a disc, since discs are still relatively hydrated and prone to bulging or prolapse under strain.
• 40s and beyond: Discs naturally become thinner and more dehydrated with age, making disc-related pain less likely unless there’s a prior history of disc problems.
• 40s–60s (men): Prostate issues can sometimes present as lower back pain.
• Any age (women): Gynecological issues should also be considered as a possible contributing factor.
• 70s and 80s: There’s an increased risk of abdominal aortic aneurysm, which can be a serious medical issue requiring prompt attention.

There are also rarer causes of lower back pain that fall outside the scope of a general overview. If your pain hasn’t been properly diagnosed, it’s always worth seeing a doctor to rule out anything more serious.

What’s Happening Structurally

When someone comes in with acute lower back pain, the pain is often vague and hard to pinpoint — typically spread across both sides of the lower back, up toward the region of the 12th rib. As pain shifts from acute to chronic, it tends to become more localized and easier to identify.

A few key structures explain why:

Facet joints — Where the vertebrae overlap, small joints called facet joints can become compressed and irritated. Because these joints sit close to the nerves, inflammation here can irritate nearby nerves and trigger muscle spasm throughout the surrounding area.

Discs — The intervertebral discs act as cushions between each vertebral segment, allowing controlled movement and compression. When a disc bulges or prolapses, it releases inflammatory chemicals that sensitize nearby nerves — again resulting in muscle spasm.

Ligaments — These connect bone to bone and are generally more resilient to everyday activity. However, trauma such as a rear-end car collision can overstretch and sprain them, leading to pain.

Muscles — Both deep and superficial muscles support the spine. When someone experiences lower back pain, these muscles typically go into spasm, which is what causes the stiffness and restricted movement that make everyday tasks — like standing up or rolling over in bed — so difficult.

In short: irritation to any one of these structures triggers inflammation, inflammation affects nearby nerves, and irritated nerves cause the surrounding muscles to spasm. Reducing that inflammation and spasm is the first priority in any recovery plan.

The Root Cause Behind Most Cases: Weakness

While there are many possible triggers, one underlying factor shows up again and again: weakness in the lower back muscles.

Prolonged sitting — whether from office work, long periods on the sofa, or simply reduced activity — gradually weakens the muscles that support the spine. When these muscles can’t keep up with physical demands, the spine loses stability, and that extra load gets transferred to the discs and ligaments instead, wearing them down over time.

This weakness is also compounded by tightness. One of the most common pain points is where the erector spinae muscles attach near the base of the spine, close to where the pelvic bone meets the sacrum. Sudden increases in activity — moving house, a weekend of gardening — can overwhelm muscles that simply aren’t conditioned for the demand, triggering irritation, spasm, and pain that spreads across the lower back.

This creates a frustrating cycle for chronic sufferers: pain leads to inactivity, inactivity leads to further weakness, and further weakness leads to more pain. The only way to break that cycle is to rebuild strength in the lower back — gradually and correctly.

Acute vs. Chronic Lower Back Pain

Recognizing which type of pain you’re dealing with is key to recovery:

Acute pain typically results from a recent event — something that happened today, yesterday, or within the last week to ten days. It’s usually intense (often rating 7–9 out of 10), accompanied by significant stiffness, and made worse by movement. Sitting still may feel relatively fine, but transitional movements — standing up from a chair, rolling over in bed — can be genuinely difficult. Acute pain generally lasts around one to one and a half weeks before starting to ease.

Chronic pain has persisted for weeks, months, or even years. It tends to be less intense (often 3–5 out of 10) but far more localized — patients can usually point to exactly where it hurts, unlike the vaguer, more widespread discomfort of acute pain.

A Three-Phase Approach to Recovery

Recovery generally follows three phases, and knowing which phase you’re in shapes what you should actually be doing:

Phase 1 — Get out of pain. If you’re in significant, acute pain (a 6 or higher) and struggling with basic movement, this is where you start. The focus is gentle movement, reducing inflammation, and calming the nervous system — think light massage and ice, not aggressive stretching or exercise.

Phase 2 — Restore movement. Once pain has dropped to a more manageable level (around a 3–5), the focus shifts to stretching and rebuilding flexibility and mobility.

Phase 3 — Rebuild strength. Once flexibility has returned to normal (or better), it’s time to strengthen the muscles that support the lower back — using bodyweight and resistance work to build lasting resilience and reduce the risk of recurrence.