There is local inflammation of tendon which is going towards the finger alongwith local obstruction by the ligament pulley.. This is the reason for Trigger finger..
Next Steps
You may start with hot fomentation, take analgesic and anti inflammatory medicine.. Physiotherapy can also be started.. If the problem persists, you may require local steroid injection.. that will help in reducing the inflammation.. If the problem persists or recurs, then surgical treatment may be required in few cases..
Health Tips
Use a splint for support to avoid flexion of finger..