Accidentally hammering off

Ok, so this is not a problem I thought I wouldn't want since when I _want_ to hammer off, it never happens with sufficient volume, but I've found that when I'm moving from an E major chord (bar the G, C, E on the fourth fret and index on the second fret) to...well, anywhere, I accidentally hammer off, usually on the barred strings. Any tips on how to avoid this?

Also, on an unrelated note, I've gotten into this habit of using the pad of my index instead of the tip of my index, which is forcing my index finger joint to hyperextend and get sore. Just wondering if anyone else has run into this before. Is it something I just get used to, or something I should fix?

I think you mean pulling off? Wash your hands and clean up the strings and fretboard (I use GHS FastFret to reduce a lot of the friction). I wouldn't worry about it too much though. Finger moisture will do that to you. Other than that, you could partially lift the chord up so the strings mute before you actually lift your fingers off the strings to soften the pull off. It's a little hard to avoid with heavy playing. You could always try different strings as well. Fluorocarbons are nice and smooth.

As for the index finger, try to lose the pad habit. It will help you a lot in the long run especially in dexterity and endurance.

Yes, sorry, I meant pulling off. I guess it's hammering on, eh...