Trigger Finger is a type of tendinitis which develops in the tendons that bend the fingers. It is also known as Flexor Tendinitis. When the flexor tendons which bend the fingers become aggravated, they can cause pain, swelling, and stiffness. It interferes with the normal movement of the tendon that causes the finger to click, catch (“triggering”) or lock in position. A finger or fingers will hardly bend and once bended, locks on its joint and is painful as it slowly straightens back.