This question is based on an observation I made when executing various trill figures..examples would include trills of 1-3-4, 1-2-4, 1-3, 1-4, & pretty much any trill involving the first finger as the lowest trill note. What I observed regarding the use of my pointer finger is that the way it behaves in its function of holding down the bass of the trill can best be described as "barresque". In other words, as I am ussing it to hold down the bass of the trill, it is not bahaving in the manner that is consistant with optimal classical technique (ie bent distill joint and having the string held down on the very tip. Is this a problem? Here is an example of one such trill where this phenomenon is particularly exhagerated in my trill execution. Its a simple trill Idea played accross 3 octaves with a rhythm of 5/beat.

e|----------------------------------------------------------------------10h12p10---10h12h13-|
b|---------------------------------------------------------10h12h13-------------13--------------|
g|-------------------------------------7h9p7---7h9h10------------------------------------------|
d|----------------------------7h9h10-------10----------------------------------------------------|
a|---------5h7p5---5h7h8------------------------------------------------------------------------|
e|-5h7h8---------8--------------------------------------------------------------------------------|

For example, great Paul Gilbert and yet another great John Petrucci use this "barresque" (great explanation man) and they're cool about it...

If it feels pain, drop it. If not, and you still want to get rid of it you'll have to turn that distortion off, because you've probably developed this type of "rude" index finger behavior for filtering unwanted overall noise produced by non-played strings while playing single note solo... I use it sometimes also, sometimes I mute with some other flash from my fingers, palm etc... it all depends on a musical idea.

I think it's cool to have the control over it, when to do it, and when not.

Pebber explained muting stuff perfectly. Something like... muting of non-played strings is done with any flesh of both hands available dictated by particular musical situation...