Gilbert, I think that cbcrow has it right. It sounds like you are getting way too much pressure on the top of the arrow nock with your index finger which can be caused by too stiff a wrist and too much weight on your middle and ring fingers. Your wrist and forearm MUST be as relaxed as possible so the weight of the string at full draw aligns your hand, not the other way around. I have a video here on the shooter's forum (second page) called "release tips", go look at that video and see if it gives you any ideas.
Also if you can post your video, it would be easier to see what you are really doing.