Since you just started playing, I think it's normal, since your fingers aren't used to those kinds of muscle movements yet. Like Eugeen said, it could also be caused by having an incorrect hand position.
If the pain worsens though, I would go see a doctor (depending on the severity of the pain, and the nature of your previous injury). I have a friend who had a sports injury in their arm muscles, and when they played piano, it worsened the previous injury.