Tendinitis or injury of the rotator cuff is often the cause for shoulder pain. The supraspinatus tendon is most often affected. There can be inflammation, fibrosis and adjacent bursitis. The supraspinatus tendon can be torn by falling on an outstretched arm or lifting a heavy object. Seen here is an MRI scan of the left shoulder demonstrating a full thickness tear of the supraspinatus tendon.