Shoulder pain (including subacromial pain)

Shoulder pain is common, and often it develops gradually — with reaching, lifting, or overhead activity, or simply over time — rather than from a single accident. When there is no clear one-time injury, the goal of an evaluation is to work out which structure is involved, because several different problems can cause similar-feeling pain.

This page focuses on shoulder pain that is not tied to a specific sudden injury. If your shoulder pain started with a fall, a dislocation, or another distinct injury, or if the concern is instability or a known tear, the pages on those specific topics may fit better.

At the top of the shoulder, the outer tip of the shoulder blade (the acromion) forms a roof over the rotator cuff — the group of tendons that help lift and rotate the arm. Between that roof and the cuff is the subacromial space, which contains a small fluid-filled cushion called the subacromial bursa.

When the bursa or the nearby cuff tendons become irritated, the result is often pain along the outer shoulder and upper arm, particularly with reaching and overhead activity. Irritation of the bursa is called subacromial bursitis. Because the bursa and the rotator cuff sit so close together, subacromial pain and rotator-cuff irritation frequently occur together and can be hard to separate.

You may hear this area of pain described as "impingement." That word describes one idea about the mechanism — the cuff and bursa being compressed under the acromion — but it does not fully explain why a given shoulder hurts, and pain in this region does not prove that anything is being permanently pinched. Many clinicians now simply call it subacromial pain, and treat it based on symptoms and examination rather than on a single mechanical label.

Subacromial pain is only one possibility. Pain in and around the shoulder can also come from:

• The rotator cuff — irritation, tendinopathy, or a partial or full-thickness tear
• The long-head biceps tendon at the front of the shoulder
• The acromioclavicular (AC) joint at the top of the shoulder, where the collarbone meets the shoulder blade
• Arthritis of the main shoulder (glenohumeral) joint
• A stiff, painful shoulder from adhesive capsulitis ("frozen shoulder")
• Instability or a labral problem, particularly in younger or more active shoulders
• Pain referred from the neck, which can be felt in the shoulder even though the source is elsewhere

These problems can feel similar but are managed differently, so part of the value of an evaluation is simply sorting out which one you have — and recognizing when more than one is present at the same time. A clear picture of the source of the pain is what makes the rest of the plan sensible.

It is also common for imaging to show changes — such as bursal thickening, a bone spur under the acromion, or wear in a tendon — that are frequently seen in people without any pain. A finding on a scan is interpreted alongside your symptoms and examination; on its own it does not necessarily explain the pain.

Shoulder pain from the subacromial space and nearby structures often includes:

• Pain along the outer shoulder and upper arm
• Pain with reaching, lifting, or overhead activity
• Pain when lying on the affected side at night
• A painful arc of motion as the arm is raised to the side
• Aching that lingers after activity

Evaluation usually begins with the story of your symptoms — how the pain started, what makes it better or worse, and how it affects sleep and daily activity — followed by a physical examination of the shoulder, and often the neck, to sort out where the pain is coming from.

X-rays are used to look at the bones, the space beneath the acromion, and any arthritis when that is relevant. Ultrasound or MRI is used selectively — to look at the rotator cuff, bursa, and nearby structures when the diagnosis is uncertain or when more detail would change the plan. Imaging is not always needed, and its findings are weighed together with your symptoms and examination rather than on their own.

Most shoulder pain of this kind improves with nonsurgical care, and that is usually where treatment starts. Care is individualized and may include:

• Activity modification — adjusting or temporarily reducing the activities that provoke the pain
• Rehabilitation that restores motion and builds rotator-cuff and scapular (shoulder-blade) strength and control
• Medication when appropriate, as advised by your clinician
• In selected situations, a corticosteroid injection into the subacromial space may be considered to reduce inflammation and help you engage in rehabilitation; whether an injection is used is an individual decision made with your clinician
• Time — many of these problems settle over weeks to months as the shoulder is rehabilitated

For most people with subacromial pain, a well-conducted course of nonsurgical care is the mainstay. Surgery is considered selectively — usually when meaningful symptoms persist despite an appropriate trial of nonsurgical treatment, and when the examination and imaging point to a problem that an operation could reasonably help.

What kind of surgery, if any, depends on the underlying cause. A rotator-cuff tear, a biceps problem, AC-joint arthritis, or glenohumeral arthritis are each addressed differently. For subacromial pain specifically, an arthroscopic subacromial decompression is one option that is used in selected situations rather than routinely; the treatment page explains what it involves and why it is not automatically beneficial for everyone.