I think the general term for this is Obstacle.
FWIW, I see Conflict as something much more dynamic (or rather, as dynamic as it has to be to fill the allotted time it's going to take up).
I want to go to Vegas, but my car has no gas and I have no money. That's an obstacle.
I want to go to Vegas, but my wife doesn't want me to go because she knows that my old flame lives there and this has caused problems in the past. This is a conflict.
These things are not discrete—an obstacle can be a conflict, and vice versa.
I haven't done much thinking about positive and negative conflicts, but here is my stab at it:
An alcoholic desires booze and lacks the ability to handle it. Combined, these things amplify and result in massive uncontrol: a drunken night with friends. (At the beginning of a story, this could be experienced as subjectively good; at the end and a failed go at treatment, as subjectively bad.)
An alcoholic desires booze and lacks the ability to handle it. Combined, these things result in massive control: a long night in the kitchen of your sponsor. (How does one experience this? A good night with someone trying to recover, or a bad night with someone desperately struggling?)
Hmm... having written this out, I found it useful, but not as a way of understanding positive and negative conflict. Both seem to amplify what's going on. Maybe without a Goal or a Concern we can't really think about this very easily. It's like everything in the story is linked!