Middle finger into palm is sore & hurts. dr said trigger finger. could it be infection instead? no swelling or redness. no injury to hand. only middle

Not likely infection: Trigger finger is more common (especially in the dominant hand) in a healthy individual with no history of trauma, no redness, swelling. There is often a mass that can be felt and move with flexing and extending of the finger. If infection is present a present usually doesn't tolerate moving the finger. Trust your physician. If you have doubts "see" another physician.