Where it hurts is a clue, not a diagnosisEmerging evidence
A study of 94 people at an English hospital mapped where shoulder pain was felt against the final diagnosis. Rotator cuff pain was mainly sharp, around the front of the shoulder, and ran down the arm, and rotator cuff tears followed the same pattern; AC joint pain was sharp and well localised to the front and top; and arthritis of the shoulder joint affected the whole arm.
But when the maps were tested in 194 new patients, reading the map alone named the right diagnosis only 45.4% to 49.5% of the time, although different testers agreed with each other fairly well. So this guide says a spot points to a cause rather than proving it, and an examination decides.
Sources 1, 2
The rotator cuff: the usual sourceStrong evidence
NHS inform calls subacromial pain syndrome, pain from the rotator cuff tendons and the fluid sac above them, the most common reason for shoulder pain. Its main symptom is pain in the upper arm with lifting the arm above shoulder level and reaching behind your back, for example putting a jacket on, and lying on that shoulder can be hard. In the pain-mapping study it was felt mainly around the front of the shoulder.
Rotator cuff tears are more likely over 40, often cause pain at rest and at night, and weakness lifting or turning the arm, the American Academy of Orthopaedic Surgeons (AAOS) says, and some cause no pain at all. The AAOS adds that bursitis of the sac above the cuff often comes with rotator cuff tendinitis, which overhead throwing or work can bring on.
Sources 3, 1, 4, 5, 6
The biceps tendon in its grooveStrong evidence
The long head of the biceps runs over the front of the shoulder through a groove in the arm bone. Biceps tendinitis causes pain or tenderness at the front of the shoulder, worse with overhead lifting, sometimes with an ache down the upper arm or a snapping feeling, and the AAOS says it usually comes along with other shoulder problems: rotator cuff wear or tears, arthritis, labral tears or a shoulder that keeps slipping.
A torn long head of the biceps causes sudden sharp pain in the upper arm, sometimes a pop, bruising, cramping and a bulge low in the upper arm (the Popeye sign). For most people the pain goes away over time, and the mild weakness or the bulge don't usually bother them, the AAOS says.
Sources 7, 8
The subscapularis: the cuff tendon at the frontEmerging evidence
The subscapularis is the rotator cuff muscle at the front of the shoulder, and it turns the arm inwards. In a series of 13 people with tears of it after an injury, the arm had usually been forced backwards or outwards; all had pain and weakness, with weak inward turning and tenderness over the groove at the front of the arm, and 7 of 14 shoulders also had a biceps tendon problem. Reviews say these tears are easily missed, that the lift-off, belly-press and bear-hug tests help find them, that many partial tears can be treated without surgery, and that a sudden tear diagnosed late has a different outlook from other cuff tears.
Sources 9, 10, 11
The AC joint and the SC jointStrong evidence
The AC (acromioclavicular) joint is where the collarbone meets the top of the shoulder. Its pain is sharp and well localised to the front and top of the shoulder; the NHS lists pain on top of the shoulder, where the collarbone and shoulder meet, as an AC joint problem, and the AAOS says arthritis there is felt on top of the shoulder. Most AC joint separations after a fall do well without surgery.
The SC (sternoclavicular) joint is where the collarbone meets the breastbone. It can be sprained, become arthritic or, after a hard blow, come out of place; the AAOS says a backward dislocation there can press on the windpipe, the gullet and the main blood vessels and needs urgent treatment.
Sources 1, 6, 12, 13, 14
Deep clicking and slipping: the labrum and instabilityStrong evidence
A SLAP tear is a tear at the top of the labrum, the rim of tissue around the socket, where the biceps tendon attaches. The AAOS lists locking, popping, catching or grinding, pain lifting overhead, a feeling the shoulder will pop out of joint and, in pitchers, slower throws or a dead arm. It can follow a fall onto an outstretched arm, a forceful pull, a dislocation or repeated overhead sport, and fraying of the upper labrum is part of normal ageing over 30 to 40.
The NHS lists a tingling, numb or weak arm and a shoulder that feels as if it is clicking or locking among the signs of instability. After a dislocation, the NHS says recovery usually takes 6 to 12 weeks, and up to 16 weeks to return to some sports.
Sources 15, 6, 16
Stiff in every direction: frozen shoulder and arthritisStrong evidence
Frozen shoulder most commonly affects people aged 40 to 60, more often women and people with diabetes, and its pain is usually over the outer shoulder and sometimes the upper arm, the AAOS says; the NHS says the pain can be worse at night. Arthritis of the shoulder joint is a deep ache centred at the side or back of the shoulder, with grinding and stiffness. So neither is a typical cause of pain mainly at the front, but both can sit alongside it; what marks them out is stiffness in every direction.
Sources 17, 18, 12
Causes that aren't the shoulderStrong evidence
NHS inform says shoulder problems can come from the neck even when you don't feel pain in your neck, described as pins and needles, or sharp, hot or burning pain. The NHS says call 999 for chest pain that feels tight or like squeezing, or chest pain that spreads to your arms, neck or jaw; angina can cause sudden pain in the chest, neck, shoulders, jaw or arms; and the British Heart Foundation says women's heart attack pain can spread to either arm, the neck, jaw, upper back or stomach.
Polymyalgia rheumatica causes pain and stiffness around the shoulders, neck and hips, with morning stiffness lasting more than 45 minutes, mostly in people over 65.
Sources 19, 20, 21, 22, 23
When a scan or test helpsStrong evidence
Most front-of-shoulder pain is diagnosed from the story and an examination; the NHS says a clinician might send you for tests such as an X-ray. X-rays show the bones, and an ultrasound or a magnetic resonance imaging (MRI) scan shows the tendons when a tear would change the plan, for example sudden weakness after an injury. The subscapularis has its own examination tests.
Scan findings need care: fraying of the upper labrum is part of normal ageing over 30 to 40, some rotator cuff tears are painless, and repairing or bypassing a type II SLAP lesion did no better than sham surgery. Frozen shoulder doesn't need an MRI or ultrasound to be diagnosed. After a dislocation, an X-ray confirms it. Suspected heart pain needs an electrocardiogram (ECG) and blood tests.
Sources 6, 4, 15, 24, 11, 17, 16, 20
How it usually goesEmerging evidence
The NHS says shoulder pain usually needs 2 weeks of looking after it yourself before it starts to ease, and can take 6 months or longer to recover. NHS inform expects new problems to begin to settle within 6 weeks, and says most subacromial pain improves on its own, though some takes time.
The AAOS says treatment without surgery relieves pain and improves function in about 80% to 85% of people with rotator cuff tears, and that most people with an AC joint separation, even professional athletes, return to normal function without surgery. Frozen shoulder goes through a painful freezing stage of 6 weeks to 9 months, a frozen stage of 4 to 6 months and a thawing stage of 6 months to 2 years, and full recovery can take up to 3 years. No one can promise a date.
Sources 6, 19, 3, 4, 13, 17