The Hidden Pain Source Doctors Keep Missing: Why Your Lower Back Might Not Be Your Real Problem

Your lower back pain might not actually be coming from your spine. Many patients seeking relief for what they think is a herniated disc or sciatica are actually dealing with sacroiliac (SI) joint dysfunction—a condition that often goes undiagnosed because it mimics other spinal problems so convincingly. Understanding the difference could be the key to finally getting effective treatment instead of months of unsuccessful therapy.

What Is the Sacroiliac Joint and Why Does It Matter?

The sacroiliac joints connect your sacrum (the triangular bone at the base of your spine) to your pelvis, with one joint on each side of your lower back. Although these joints move only slightly, they handle critical functions: transferring weight between your upper body and legs, stabilizing your pelvis, and absorbing shock during walking, standing, and lifting. When the SI joint becomes inflamed, irritated, or unstable, it can cause significant pain that feels remarkably similar to other lower back conditions.

The problem is that SI joint pain often gets misdiagnosed because imaging studies like MRIs don't always clearly show SI joint dysfunction. A thorough physical examination and diagnostic injections are often needed to confirm the diagnosis. This means many people spend months or even years treating the wrong condition.

How Can You Tell If Your Pain Is Coming From the Sacroiliac Joint?

SI joint pain has distinct characteristics that differ from classic sciatica or disc problems. Recognizing these signs could help you get the right diagnosis faster. The pain is typically felt on one side rather than directly in the center of your spine, usually located just below the beltline. Unlike sciatica, which often travels far down the leg, SI joint pain may spread into the buttocks, hips, or upper thighs but usually does not extend far below the knee.

Several other patterns can point to SI joint involvement:

• Positional Pain: Prolonged sitting, standing, or shifting weight to one side can aggravate SI joint irritation, and you may experience sharp pain when rising from a seated position or climbing stairs.
• Instability Sensation: Some patients describe a feeling that their pelvis is "out of place" or unstable when walking, which is a hallmark of SI joint dysfunction.
• Postpartum Vulnerability: Hormonal changes and pelvic ligament stretching during pregnancy can increase SI joint instability, making postpartum women especially susceptible to this condition.

What Causes Sacroiliac Joint Problems?

SI joint dysfunction doesn't appear out of nowhere. Several factors can trigger or contribute to the condition. Understanding your risk factors might help explain why you developed pain in the first place:

• Structural Issues: Leg length differences and arthritis can alter how weight distributes through your joints, putting extra stress on the SI joint.
• Activity and History: Repetitive impact activities, previous lower back injuries, and prior lumbar spine surgery can all increase your risk of SI joint problems.
• Related Spinal Conditions: Lumbar disc herniation, facet joint syndrome, hip joint problems, and sciatic nerve irritation can all contribute to or coexist with SI joint dysfunction.

Why Does Sitting Make Lower Back Pain Worse?

If your pain intensifies during the workday, you're experiencing a common pattern. Sitting applies approximately 90% more force on your lower back compared to standing, which explains why many people find their pain worsens throughout the day. This increased pressure occurs because sitting changes your spine's natural curves. In a healthy standing position, your spine maintains its natural S-shaped curve, distributing weight evenly. However, when you sit—especially with poor posture—your lower back flattens and your pelvis tilts forward, concentrating stress on specific spinal segments.

The prolonged nature of sitting compounds these issues. When you remain in the same position for hours, your hip flexors shorten and tighten while your glutes become weak and inactive. This muscle imbalance creates anterior pelvic tilt, where your pelvis tilts forward excessively, putting additional strain on your lower back muscles and joints. For people with SI joint dysfunction, this postural stress can be particularly problematic.

How Is Sacroiliac Joint Pain Different From Sciatica?

The confusion between SI joint pain and sciatica is understandable because they share some symptoms. However, a chiropractor with experience in differential diagnosis can distinguish between them. Sciatica involves irritation of the sciatic nerve running from your lower back down to your legs, often creating a burning or electric shock sensation that intensifies when sitting. This condition can cause pain on one side of your back and may radiate down your leg.

SI joint pain, by contrast, typically stays localized to the lower back and buttock region without traveling far down the leg. The pain pattern, location, and what triggers it are different enough that a proper physical examination can usually identify which condition you're dealing with. "Sciatica has multiple distinct causes, and each one responds to different treatment," explains Dr. Jennifer Wise, a Doctor of Chiropractic at Synergy Institute in Naperville. "Treating piriformis syndrome the same way you'd treat a herniated disc is like putting a bandage on a broken bone—you're not addressing the actual problem".

What Treatment Options Actually Work?

The good news is that SI joint pain is highly treatable. Depending on severity, options may include physical therapy focused on pelvic stabilization, anti-inflammatory medications, SI joint belts for temporary support, and image-guided SI joint injections. In select cases, radiofrequency ablation (a procedure that uses heat to reduce nerve pain) may be considered. In rare situations, surgical fusion may be considered, but most patients improve with conservative care.

The key is matching the right treatment to your specific condition. If you've been treating "low back pain" without improvement, and especially if your symptoms match the SI joint pain patterns described above, it may be time for a more targeted evaluation. Proper diagnosis is the first step toward effective relief. Sacroiliac joint pain can significantly impact mobility and quality of life, but with the right treatment plan, many patients experience substantial improvement.

If you're experiencing persistent lower back or pelvic pain that hasn't responded to standard treatments, consider asking your healthcare provider about sacroiliac joint dysfunction. You may have been treating the wrong condition all along.