Sorry to hear you're going through that Jeff.
Here's my story.
I deal with quite a bit of back pain everyday, and I have for a long time. I've been laying floor since I was 18(34 now). I've never been outworked. I used to do whatever it took to beat the other guy, carry more, do it faster, do it harder, whatever it took. If my body would physically do it, I would. I am paying for that now. The old saying rings true "Just because you can, doesn't mean you should"
Anyway, I've been through a lot in the past year. Two bulging discs, one very badly ruptured disc, two cortizone injections(veeeery uncomfortable), one surgury, and countless physical therapy. Still in pain every day.
Everyone's body is different and reacts to different treatments differently. I think mine is trying to tell me to find a different trade.
Sounds like you're refferring to the disc between your L4 and your L5 vertibrae. I know the pain and achyness you are talking about. When you sit for long periods it super painfull, when you stand for long periods its super painful, and when you lay down for too long, the same...
-Physical therapy may not help you, since it sounds like a disc problem and arthritis, but it may be worth a shot.
-Staying active helps. For me, if I stay active(as long as it is not bending and lifting and reaching) I have less pain usually. When you stay in one position it really stiffens up.
-One thing that has helped me is Voltaren. It is basically a prescription Motrin. It is an anti-inflamitory. We went through a few prescription anti-inflamitory's before we found one that works for me. I still take it twice a day. It helps, and if I miss a dose I can rerally feel it. This may be something worth trying for you
Two downsides to this medication -1 you get a little acid-reflux, and -2 they say if you're on it for over a year you need to get checked for liver function
I know I don't have any magic answer for you, sorry. But I can sympathize with you. I know what it feels like to be "too young to feel this damn old"
Good luck with this Jeff! A back is no fun to have down and out brother.
Keep us posted.