What is the best course of treatment for shoulder pain that worsens when lying on the right side?

Treatment for Position-Dependent Right Shoulder Pain

For shoulder pain that worsens when lying on the right side and improves with positional changes, the primary treatment is to modify sleeping position by avoiding lying on the affected shoulder, combined with conservative management including proper positioning, gentle range of motion exercises, and analgesics as needed.

Understanding the Mechanism

Your presentation strongly suggests positional shoulder pain, where prolonged pressure on the shoulder from the weight of the thorax during side-lying sleep causes tissue damage and subsequent pain 1. Research demonstrates a clear association between the side of shoulder pain and preferred sleeping position, with 67% of patients sleeping on their painful shoulder 2. The fact that your pain improved with changing to supine (back) sleeping confirms this positional relationship 1.

Primary Treatment Strategy

Immediate Positional Modifications

• Avoid sleeping on the right shoulder entirely - this is the most critical intervention based on the causal relationship between decubitus position and shoulder pain 1, 2
• Sleep on your back as you've already discovered provides relief 1
• If sleeping with a partner, consider switching sides of the bed to naturally encourage turning away from the painful shoulder 2
• If you must side-lie, sleep on the left (unaffected) side only 1

Conservative Management Approach

First-line interventions 3:

• Analgesics: Start with acetaminophen or ibuprofen if no contraindications exist 3
• Gentle range of motion exercises: Focus on passive and active-assisted movements, particularly external rotation and abduction, to prevent stiffness 3
• Proper positioning during daytime: Maintain neutral shoulder alignment when sitting or resting 3

Adjunctive symptomatic relief 3:

• Ice or heat application for pain control 3
• Soft tissue massage for muscle tension 3

When to Escalate Care

Imaging Considerations

If symptoms persist beyond 4-6 weeks despite conservative management, initial radiographs are appropriate as the first screening modality for shoulder pain 4. Standard shoulder radiographic series should include at least 3 views with 2 orthogonal projections 4.

If radiographs are noncontributory and clinical suspicion suggests 4:

• Bursitis or biceps tenosynovitis: MRI without contrast (rated 9/9) or ultrasound (rated 9/9) are equally appropriate 4
• Labral tear or instability: MR arthrography is preferred (rated 9/9) 4

Referral Indications

Refer to orthopedic surgery if 5:

• Acute traumatic injury occurs
• "Red flag" diagnoses are suspected
• Failed appropriate course of non-surgical treatment (typically 12-16 weeks) 5, 6

Critical Pitfalls to Avoid

• Do not use overhead pulley exercises - these promote uncontrolled abduction and can worsen shoulder pathology 3
• Do not delay treatment - persistent shoulder pain can lead to frozen shoulder, inhibit function, and contribute to depression and reduced quality of life 3
• Do not perform aggressive passive range of motion - if done improperly, this can cause more harm than good 4

Expected Timeline

Most positional shoulder pain should improve within 4-6 weeks of consistent positional modification and conservative management 1, 5. The discrepancy between the prevalence of side-sleeping and shoulder pain suggests that only those who maintain prolonged immobility in the same position develop symptoms 1. Your rapid improvement with position change is an excellent prognostic sign.

Strengthening Phase

Once acute pain is controlled, initiate strengthening exercises for rotator cuff and scapular stabilizers 3. This typically occurs after 2-4 weeks of pain control and should be guided by symptom response 3.