Volume output crazy

I can't reproduce the exact sequence of events when this happens, because I think it changes but...when I plug my headphones in the volume automatically adjusts itself to maximum. But it doesn't always do it right away, just the first time I go to adjust the volume after I put the headphones in. Anyway, it's hurt my ears more than once. After the second time it happened, the first time I thought it was an anomaly, I took to turning the volume all the way down before I put the headphones in, then making sure I adjusted it before I would put the headphones in, but then if I insert a DVD it just turns itself to maximum anyway. Do you think this has something to do with that F3 key function? It's killing me. I hope this is clear.

I know with my black macbook the audio automatically lowers when I insert my headphones. It has a separate volume for with and without the headphone jack being used. It simply remembers the volume I lasted when used my heaphones. I'm assuming your using the macbook volume and not the separate volumes within itunes and dvd player.