Sleeping on One Side and Contralateral Scapula Pain
No, sleeping on one side does not cause scapula pain on the contralateral (opposite) side—the evidence consistently shows that shoulder and scapular pain occurs on the ipsilateral (same) side that you sleep on, not the opposite side.
The Evidence for Ipsilateral Pain
The relationship between sleep position and shoulder/scapular pain is well-established, but the pain occurs on the side you sleep on:
A cross-sectional study of 83 patients with unilateral shoulder pain found that 67% slept on their painful shoulder, demonstrating a significant association between the side of sleep and the side of pain (P = 0.02) 1
A preliminary study comparing laterality of shoulder pain with sleep position found strikingly similar laterality ratios, suggesting a causal relationship between sleeping on a particular side and developing pain on that same side 2
Mechanism of Ipsilateral Pain
The pain mechanism involves direct pressure and postural strain on the dependent (down) side:
Prolonged pressure on the shoulder from the weight of the thorax during side-lying sleep can produce enough tissue damage to cause subsequent shoulder pain on that same side 2
Scapular depression (which occurs on the weight-bearing side during lateral sleeping) maintains the upper trapezius muscle in a lengthened position, causing excessive strain and lowering pain thresholds in that region 3
The ASA guidelines note that in lateral decubitus positioning, chest rolls are recommended under the dependent (down) lateral thorax to decrease risk of brachial plexus neuropathy in the down arm, not the up arm 4
Clinical Implications
If you're experiencing scapular pain:
Evaluate which side you predominantly sleep on—the pain should correspond to your preferred sleeping side 2, 1
Consider changing your sleeping position or alternating sides more frequently during the night 1
For patients sleeping with a partner, 76% sleep on the side opposite their partner (turning away), which may contribute to consistent unilateral positioning 1
Important Caveat
Sleep posture does affect neck and shoulder muscle activity bilaterally, but asymmetrically—for example, sleeping supine with the dominant hand on the forehead increases upper trapezius and scalene activity on the right side significantly 5. However, this represents increased muscle activity rather than contralateral pain from lateral sleeping.
The postural theory suggests that to develop pain, subjects likely need to spend longer periods in the same decubitus position without changing positions compared to the average person 2.