What could be causing intermittent pain in the soleus muscle of my right leg that improves with massage or elevation and worsens with inactivity?

Differential Diagnosis: Soleus Pain with Relief from Elevation and Massage

Your symptoms strongly suggest either Restless Legs Syndrome (RLS) or soleus muscle tendinopathy, with RLS being more likely given the paradoxical worsening with rest and relief with movement/position changes.

Primary Consideration: Restless Legs Syndrome

The pattern you describe—pain worsening during inactivity, relief with movement and leg elevation, and temporary improvement with position changes—meets the diagnostic criteria for RLS 1.

Diagnostic Criteria for RLS

Your symptoms align with the essential diagnostic features 1:

• Unpleasant sensations in the legs (your soleus pain)
• Symptoms begin or worsen during rest/inactivity (you note pain increases with no activity)
• Partial or total relief with movement (shifting leg position, crossing legs provides temporary relief)
• Symptoms worse in evening/night (though you didn't specify timing, this should be assessed)

Initial Assessment Steps

Check serum ferritin level immediately 1. Values less than 50 ng/mL are consistent with RLS diagnosis and indicate need for iron supplementation 1.

Perform a thorough neurological examination to exclude secondary causes including peripheral neuropathy or radiculopathy 1.

Treatment Algorithm for RLS

If ferritin <50 ng/mL: Start iron supplementation first 1.

If pharmacologic therapy is required: Dopamine receptor agonists are first-line treatment 1:

• Ropinirole: Start 0.25 mg orally 1-3 hours before bedtime, increase to 0.5 mg after 2-3 days, then 1 mg after 7 days, with weekly 0.5 mg increments up to maximum 4 mg at week 7 if needed 1
• Pramipexole: Start 0.125 mg orally 2-3 hours before bedtime, double every 4-7 days to maximum 0.5 mg 1

Critical pitfall: Monitor for augmentation (worsening symptoms, earlier onset, spread to other body parts), which is common with levodopa-carbidopa but less frequent with newer dopamine agonists 1.

Secondary Consideration: Soleus/Achilles Tendinopathy

If RLS criteria are not fully met or symptoms are more consistently activity-related, consider tendinopathy 1.

Diagnostic Features of Tendinopathy

• Insidious onset of load-related pain coinciding with increased activity 1
• Well-localized tenderness on palpation of the gastrocnemius-soleus complex 1
• Pain described as "sharp" or "stabbing" 1
• Thickening and tender, palpable nodules on examination 1

Treatment Algorithm for Tendinopathy

First-line conservative management 1:

• Eccentric strength training is the most effective treatment, stimulating collagen production and promoting tendon healing 1, 2
• Relative rest: Reduce repetitive loading activities but avoid complete immobilization which causes deconditioning 1, 2
• Deep friction massage of the gastrocnemius-soleus complex reduces pain 1, 2
• Stretching exercises for the gastrocnemius-soleus complex 1

Pain management 1, 2:

• NSAIDs (oral or topical) for short-term relief only—they do not affect long-term outcomes 1, 2
• Topical NSAIDs preferred due to fewer systemic side effects 1

Critical pitfall: Never inject corticosteroids into the tendon substance—this inhibits healing, reduces tensile strength, and predisposes to spontaneous rupture 2. While corticosteroid injections may provide short-term pain relief, they do not change long-term outcomes 1.

Heel lift orthotics may help unload the tendon for pain relief 1.

Expected timeline: Approximately 80% of patients recover within 3-6 months with appropriate conservative treatment 2.

Surgery consideration: Only after 3-6 months of well-managed conservative treatment has failed 1, 2.

Ruling Out Vascular Disease

Given the relief with elevation, peripheral artery disease (PAD) is less likely but should be excluded 1.

PAD typically presents with 1:

• Exertional leg symptoms that worsen with progressive exercise
• Relief within 10 minutes of rest
• Pain described as cramping, aching, or tired/fatigued feeling
• Symptoms do NOT improve with leg elevation (in fact, ischemic rest pain worsens with elevation and improves with dependency) 1

Your symptoms improve with elevation, which is opposite to PAD patterns 1.

If vascular concerns persist, obtain ankle-brachial index (ABI) measurement 1.

Recommended Diagnostic Approach

1. Check serum ferritin level to assess for RLS 1
2. Perform neurological examination to exclude neuropathy/radiculopathy 1
3. Palpate soleus/Achilles complex for tenderness, thickening, or nodules 1
4. Assess timing: Do symptoms worsen in evening/night (suggests RLS) or with specific activities (suggests tendinopathy)? 1
5. Consider imaging only if diagnosis unclear after history and physical examination, or if symptoms persist despite 6-8 weeks of conservative treatment 1

If multiple symptoms or tendons are involved, evaluate for underlying rheumatic disease 1, 2.