Common causes of shoulder pain

Rotator cuff impingement or tendinopathy:
Pain with abduction, external rotation
Subacromial tenderness
Normal range of motion with positive impingement tests (eg, Neer, Hawkins)

Rotator cuff tear:
Similar to rotator cuff tendinopathy
Weakness with abduction & external rotation
Age over 40

Adhesive capsulitis (frozen shoulder):
Decreased passive & active range of motion
Initial painful phase followed by stiffness worse than pain

Biceps tendinopathy/rupture:
Anterior shoulder pain
Pain with lifting, carrying, or overhead reaching
Weakness (less common)

Glenohumeral osteoarthritis:
Uncommon & usually caused by trauma
Gradual onset of anterior or deep shoulder pain
Decreased active & passive abduction & external rotation