I've been playing around with some backing tracks (november rain, knockin' on heaven's door etc). What I wud do is, play it in the background and use the pentatonic scale for the key.

As I was playing, I noticed that I wasn't paying too much attention to the chord changes. I was just playing what came to my mind. I tried listening to the chord changes and putting in note choices. But then, my solo sucked. It was neither fast nor interesting.

So, what I'm doing here... is it a correct approach? Or am I breeding a bad habit? :-o
Epiphone Les Paul Custom Pro (Alpine White)
J&D Strat-copy electric (Black)
Digitech RP90 modelling guitar processor
I wouldn't say it's a bad habit really. If you can play what you think sounds good then it's good. However, I think it's good to be aware of the chord changes. Try to find notes that sound good with each chord and approach them as the chord changes.
There's not really a right or wrong, you should do what works best for you, but I usually find I do a better job when I can internalize/anticipate the chord changes.
What you're trying to do is much, much more complicated than just soloing around in the pentatonic for the scale.

Expect it take time and effort before you're producing results that way.
Do you record yourself playing? I find that can open up realizations about your playing.

One simple technique that I find is pretty effective is, if you stumble on a lick or rhythm that sounds cool - play it again. After I started doing that, I noticed more musicians out there doing the same thing. You hear a cool lick, and then you hear it again - maybe in a slightly different way.

I think it's good to know where the song/progression is going if only to plan the energy path and feel of your solo so it compliments the song. Most solos seem to build upwards towards the end energy-wise, but not all the time. Also, hitting certain notes to compliment certain chords is pretty key, especially in jazz.

I guess my advice is, try planning out some cool notes in advance that you know sound good with the upcoming chord(s). Good luck!