Why Does Shoulder Pain Get Worse at Night?

The shoulder pain you can put up with during the day flares once you get into bed; you cannot turn onto that side, and your sleep keeps breaking. This is a very common complaint, and it is not simply a matter of “sleeping the wrong way” — there are real physiological reasons behind it. This article looks at why shoulder pain gets worse at night, in which conditions it stands out, and what actually helps.

Why does shoulder pain get worse at night?

So why does shoulder pain flare particularly at night? There is no single reason; several factors come together. During the day we move, and this movement clears the inflammatory chemicals that build up around irritated tissues, working almost like a pump. When you lie still for hours overnight, this “pump” stops, and inflammation and swelling can accumulate in the area. Added to this, cortisol — the body’s own natural anti-inflammatory — drops to its lowest level at night; in other words, the body suppresses pain less while you sleep. And without all the things that keep you occupied during the day, in the quiet the brain focuses more on the pain signal. The result: pain that is bearable in the daytime becomes prominent at night.

Why does lying on that side hurt more?

Lying on the painful shoulder makes the pain noticeably worse for most people. The reason is simple: when you lie down, the shoulder structures (the tendons and a small cushion called the bursa) are compressed under your body weight — and the gentle “decompressing” effect gravity provides while you are upright through the day is lost as well. Lying on that side therefore increases the pressure on tissue that is already irritated.

Which shoulder problems cause night pain?

Night pain can appear in many shoulder problems, but it stands out especially in rotator cuff problems, inflammation of the bursa (bursitis) and frozen shoulder. In frozen shoulder, in fact, night pain is often the first and most distressing symptom. In other words, “shoulder pain that worsens at night” is not one disease but a shared symptom of an underlying problem — which is exactly why the solution lies in addressing that underlying condition.

Sleeping position and what you can do at home

Sleeping position is not the “cause” of the pain on its own, but it can make an existing problem more noticeable. Avoiding lying on the painful shoulder, and supporting the arm with a pillow when lying on your back or on the good side, brings relief to most people. These are temporary relievers, though; the way to reduce night pain lastingly is to address the underlying shoulder problem.

How is it treated?

Because night pain is a symptom of an underlying condition, lasting relief is only possible by targeting that condition. A well-chosen physiotherapy programme involves managing the pain, strengthening the muscles around the shoulder and their movement control, and restoring the shoulder’s movement harmony with manual therapy. The aim is not just to get through the night, but to give your sleep back for good by addressing the source of the pain. For an overview of this and other shoulder structures, see the Shoulder Problems page.

When should you seek an assessment?

If night pain is regularly disrupting your sleep, has been going on for weeks, or is making it increasingly hard to lift your arm, a physiotherapy assessment clarifies the underlying condition and the programme that suits you. Pain that starts after a sudden trauma, or that comes with marked weakness, calls for earlier assessment.

References

1. Rotator Cuff Disease / Subacromial Pain — StatPearls / NCBI.
2. Adhesive Capsulitis (Frozen Shoulder) — StatPearls / NCBI.
3. Subacromial bursitis and night pain — clinical review literature.