Which of the following best describes the symptoms of tendinitis?

Tendinitis is an inflammation or irritation of a tendon, which is the tissue that connects muscle to bone. The hallmark symptoms of tendinitis include localized pain and tenderness in the affected area, often exacerbated by movement. This pain typically intensifies during activities that require the use of the tendon involved, making it particularly notable when a person tries to stretch or engage in movements that require them to use the affected muscle and tendon.

In contrast, other options relate to different musculoskeletal issues. Sudden, dull pain may suggest an acute injury or strain but does not specifically characterize tendinitis, which usually develops gradually over time due to repetitive use. Stiffness and swelling in joints are more typical of joint conditions such as arthritis rather than tendinitis, which is more focused on tendon pain rather than joint symptoms. Lastly, pain and soreness in muscles might indicate a muscle strain or injury, but tendinitis specifically involves tendon irritation rather than the muscle tissue itself. Thus, the symptoms best align with the description that pain worsens with movement, as this is a defining characteristic of tendinitis.