I'm a little dubious about the recliner idea because of your lower back issues. Unless it's a chair well designed for lower back pain, as a person who had lower back problems a couple of times (fixed them with physical therapy) I can't imagine that sleeping in a chair given after a while you're going to slump into odd positions will be great for the lower back. The best thing to do with any type of pain is try to figure out why it hurts. Then you might be able to fix it. The longer you let an injury last the worse it gets and the more ingrained it gets. I understand. I had an awful and apparently permanent bad reaction to a med years ago that destroyed my nervous system and so I'm now scared of pretty much everything to the point where I stopped going to docs for pain. Also the fact they weren't that great at diagnosing or fixing anything, but I'm unlucky. You probably aren't. So go get diagnosed. Maybe it's rotator cuffs. Maybe both the back and the shoulders are muscle related and can be worked back into good shape with some exercises. I have two bad hips and a bad neck and a bad left arm, which is what happens when you're very active and a drug destroys your ability to sleep. And so I know, I'm also a side sleeper, and I wake up a lot because of the drug and so I'm always lying on something that hurts. Oddly enough, however, I did fix the lower back, and part of that was putting a pillow between my knees when I sleep. Most of it was physical therapy. Even if you have a problem with the lower back and also have a condition, it doesn't necessarily mean the condition is the source of your pain directly. It might be indirect, as things you did caused muscle problems and while your condition may be hard or impossible to treat the muscles around the area aren't. As for the shoulders, though, go to the orthopod, get MRIs, find out what's wrong with them, and go from there. Because as long as they hurt and you have no problem for tackling the underlying cause of the pain you're pretty much stuck. As I've learned. Peace.
I have been sleeping in my recliner that goes almost flat for several years, but I do not use it in the flat position. I have chronic back pain and a chronic coughing so I cannot lie flat. I take one temazepam and one dose of melatonin and that works for me to put me asleep.