Trigger finger, or stenosing tenosynovitis, develops when a flexor tendon in your hand becomes inflamed and swells. The result is pain and stiffness in the finger that the tendon controls. A tender bump is also likely to appear at the base of the affected finger, near your palm. You could experience a catching or locking sensation when you move your trigger finger.
Symptoms are usually mild at first, but the condition typically worsens. Eventually, you may be unable to straighten your finger if it locks into position when bent. Trigger finger can affect any digit but is most likely to occur in your ring finger. You can also get trigger thumb.