I think i have trigger finger from what a doctor here told me, so why does it snap at night and then go away during the day,makes it hard to sleep cause then it hurts my whole arm,going to try and get a finger shint today since i'll be near walgreens?

Joint disorders of any kind, especially chronically arthritic, do best when there is opportunity for motion on an ongoing basis, allowing more flexibility and less stiffness. At night, sleep would immobilize and make symptoms worse temporarily upon awakening from sleep. See an orthopedic hand specialist.

See a hand surgeon as this is a very simple problem to remedy with either a steroid injection or a small surgery. It is the fact that you are not moving the digit at night that allows it to lock in to position. This improves but likely doesn’t resolve with movement throughout the day.