I also have DDD and unfortunately, mine is more often on the painful side than not. There are some days where it's not as bad, though, so it can wax and wane somewhat. Mine gets much worse with weather changes and humidity. And I keep getting disk bulges and herniations, sometimes it seems like every few weeks. Anti-inflammatories may help, although they are not good for the long term, but may help when flares are worse. The med that works best for me is prednisone. When I take steroids, it's almost as if I have no spine problems. But, that is even worse over the long term and is not usually prescribed for DDD. I do have other problems and I have taken Medrol Dose Packs (another steroid) for sciatica or other nerve pain flare ups and it does help. But one cannot take these for long, either.
So they say, exercise can help, though one should see a PT for the exercises best for them. Although swimming is usually the best exercise for these kinds of issues, as it puts no stress on your spine or other joints. However, exercise is still not a guarantee that it will help. In my case, I've been doing my PT exercises for over 2 years now and I still get bad pain in my spine (and elsewhere)....although I wonder how much worse it might be if I didn't exercise at all. It's just such a hard thing to deal with. I've had to really change the way I do things, but now I've pretty much gotten used to it.