What muscles could cause lower back left side pain?

Muscles that may contribute to lower back left side pain include iliocostalis lumborum, lumbar rotator, psoas major, gluteus medius, piriformis, external oblique. Trigger points, strains, or weakness in these muscles can refer pain to this area.

Lower Back

Lower Back Left Side

Q: What causes pain in the lower back left side?

Common causes of lower back left side pain include unilateral muscle strain from twisting or bending, left sacroiliac joint dysfunction, quadratus lumborum trigger points, left-sided disc herniation irritating a nerve root, psoas tightness from prolonged sitting. The specific cause depends on the nature of the pain, how it started, and which movements aggravate it.

Left-sided lower back pain may involve the left erector spinae, quadratus lumborum, or psoas muscle. Unilateral lower back pain can result from muscle strain, sacroiliac joint dysfunction, or nerve irritation on that side.

Medical Disclaimer

This information is for educational purposes only and does not constitute medical advice. Consult a qualified healthcare provider for proper diagnosis and treatment of any pain or medical condition.

Common Causes

Unilateral muscle strain from twisting or bending

Left sacroiliac joint dysfunction

Quadratus lumborum trigger points

Left-sided disc herniation irritating a nerve root

Psoas tightness from prolonged sitting

Muscles in This Area

Lower Back

iliocostalis lumborum

Iliocostalis lumborum is the lumbar erector spinae muscle along the back, from iliac crest to lower ribs, maintaining upright posture and spinal extension. Critical for deadlifts, squats, and anti-rotation core work.

Lumbar strainErector spinae myofascial painThoracolumbar fascia syndrome

Lower Back

lumbar rotator

Lumbar rotators (multifidus and rotatores lumborum) are deep spinal muscles that rotate and stabilize individual lumbar vertebrae. They prevent twisting injuries during rotational lifts like Russian twists. Essential for core stability in CrossFit and golf swings.

Lumbar facet syndromeMultifidus dysfunction

Abdomen

psoas major

The psoas major is a deep hip flexor from spine to thigh, lifting knees in running/squats. Core to posture and power; tightness causes low back pain.

Psoas syndromeIliopsoas tendinopathy

Hip

gluteus medius

Side hip muscle for abduction and stabilization during single-leg stance in running, squats. Prevents Trendelenburg gait.

Gluteal tendinopathyTrochanteric bursitisGreater trochanteric pain syndrome

Hip

piriformis

The piriformis is a deep hip rotator in the glutes, externally rotating the hip for balance in squats and deadlifts. Tightness often causes sciatica-like pain. Essential for hip mobility in athletes.

Piriformis syndromePiriformis tendinopathy

Abdomen

external oblique

External obliques form the outer 'V' of your abs on each side, rotating and side-bending the torso while compressing the abdomen. They're powerhouse muscles for rotational power in sports like golf, boxing, and throws. Train them for a defined waist and core stability.

External oblique strainSports hernia (athletic pubalgia)Abdominal wall hematoma

Stretches That May Help

Child's pose

Seated forward bend

Side bend stretch

Supine spinal twist

Thread the needle

Seated rotation hold

Lunge hip flexor stretch

Psoas release pose

Warrior lunge

Side lying IT band stretch

Figure four supine

Clamshell reverse

Figure-four stretch

Piriformis foam roll

Seated piriformis stretch

Seated twist

Windmill stretch

Recommended Exercises

When to See a Doctor

Seek medical attention if pain radiates down the left leg, you experience numbness in the groin or leg, or if the pain is accompanied by urinary changes or fever.