If you are experiencing a dull, persistent ache in the side of your shoulder that spikes when you reach overhead, lift weights at the gym, or try to settle into bed at night, you aren’t alone. Shoulder pain is one of the most common musculoskeletal complaints in New Zealand, accounting for a significant portion of ACC-funded physiotherapy consultations every year.

A frequent culprit behind these symptoms is rotator cuff tendinopathy. Understanding why this happens, and how to manage it, is the first step toward reclaiming your active lifestyle.

What is Rotator Cuff Tendinopathy?

The rotator cuff is a crucial group of four muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) and their tendons that form a sleeve around the shoulder joint. Their primary job is to hold the arm bone securely within the shallow shoulder socket, providing dynamic stability whenever you move your arm.

Tendinopathy occurs when the workload placed on these tendons exceeds their current capacity to heal, leading to localized tissue irritation and microstructural changes. Rather than a sudden tear, it is typically a progressive overuse condition. It is especially common among gym-goers, swimmers, manual laborers, and individuals over 40 whose tissues naturally take longer to recover from load.

Why Does It Hurt Most During Overhead Lifting and Sleeping?

1. The Overhead Impingement Zone

When you lift your arm above shoulder height—such as performing an overhead shoulder press, reaching for a high shelf, or painting a ceiling—the space between the top of your arm bone (humerus) and the roof of your shoulder (acromion) naturally narrows. If the rotator cuff tendons are already irritated or slightly swollen, this compression causes a painful pinch. Poor scapular (shoulder blade) mechanics or an abrupt increase in your training volume can aggravate this compression further.

2. The Night-time Ache

Sleeping with shoulder pain can be incredibly frustrating. When you lie directly on the affected shoulder, you compress the inflamed tendon against the joint structure. Conversely, lying on your opposite side can cause the injured arm to drape across your body, placing the tendon under a prolonged, uncomfortable stretch. Furthermore, the lack of movement at night reduces local blood circulation, allowing inflammatory byproducts to pool and cause that deep, throbbing ache that wakes you up.

Active Management: Moving Beyond “Complete Rest”

Historically, standard advice for a sore shoulder was to stop moving it and wait for the pain to pass. However, modern sports medicine has established that complete rest actually weakens tendons, reducing their tolerance to load and delaying long-term recovery.

An effective, evidence-based physiotherapy management plan focuses on strategic loading and lifestyle modifications:

• Modify, Don’t Stop: Instead of cutting out the gym entirely, adjust your training. Swap overhead barbell presses for a landmine press or an incline dumbbell press, which place the shoulder in the safer “scapular plane” (roughly 30 to 45 degrees forward of your chest).
• Optimize Your Sleep Ergonomics: If you prefer lying on your back or your uninjured side, support your sore arm by resting it on a pillow placed across your chest. This keeps the shoulder joint in a neutral position and minimizes mechanical stress on the tendon overnight.
• Progressive Loading Exercises: Tendons respond remarkably well to resistance. Rehabilitation usually begins with isometric exercises (holding a static contraction against resistance without moving the joint) to reduce acute pain, before progressing to eccentric and concentric strengthening to rebuild the tendon’s load-bearing capacity.

When to Seek Professional Guidance

Because shoulder mechanics are highly complex, an individualized assessment is essential. A comprehensive physiotherapy evaluation can help pinpoint specific muscular imbalances, analyze your lifting technique, and ensure you are performing the correct exercises at the right intensity.

Under the Accident Compensation Corporation (ACC) scheme in New Zealand, if your shoulder pain was triggered by a specific event—such as a sudden lifting mishap, a heavy pull, or a fall—you can lodge an ACC claim directly through a physiotherapist without needing a prior GP referral, making timely, professional rehabilitation highly accessible.

References

1. Lewis, J. (2016). Rotator cuff tendinopathy: Navigating the diagnosis-management conundrum. Journal of Orthopaedic & Sports Physical Therapy, 46(11), 919-929.
2. Cook, J. L., & Purdam, C. R. (2009). Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. British Journal of Sports Medicine, 43(6), 409-416.
3. Accident Compensation Corporation (ACC). (2025). Injury Statistics and Musculoskeletal Management Guidelines for Primary Care. Wellington, New Zealand.