Here is a small picture to show the exact location of my pain :

It's just before the articulation.
I always had this pain (for 10 years), but it's becoming harder and harder to ignore.
I feel like it is my finger extensor tendon that is over tense, you know, like if my index finger wasn't flexible enought...
My flute has inline-G. Maybe an Offset-G would help?
Did anyone have experienced a such problem?
Thanks, Pock'