As I mature, which translates to "getting older and more cranky", I am always looking for different ways to improve my movement quality while opening up joints and mobilizing damaged tissue. One of the best ways I have found to get my chest, shoulders and upper spine moving (the way they are supposed to) is by using Indian Clubs on a daily basis. I have a set next to my desk that I use while I'm writing to not only give myself a mental break, but to also "reset" on my back and shoulders from long hours in front of the computer. I also have a variety of Indian Clubs that at the gym that I use as part of my own personal warm-up before each and every training session.
If you've never worked with the Indian Clubs I strongly suggest that you look into them. They are a relatively inexpensive addition to your training equipment and will quickly pay for themselves when you realize that you are moving and feeling better. If you are already using them - then good for you - you're already ahead of the curve!
BTW - click on the image below to watch an animated GIF of me swinging two different sets of Indian Clubs. Watch carefully and you can see which shoulder I am currently rehabbing! :)