Back muscles are very small and have low stretching abilities. With age, they become less elastic. Inflamation can really mean many different things. If the center of the muscle is the inflamed section and the nerve is ok, you may recover in one or two weeks, doing nothing and taking aspirin.
In your case, probably the tendon section of the muscle is inflamed. The cells in that secction are less elasic and more delicate.
A list of things that work:
Aspirin and other anti inflamatories. In the long term, vary and alternate te use. Too much of any specific anti-inflamatory will have secondary effects.
Collostrum, Synertex Collostrum is the best by far. You can buy it at their site. Collostrum has aminoacids that include titin, the elastic portion of the collagen cell.
Bromelaid. This pinaple extract is an anti inflamatory that has no secondary effects. It sells in any vitamin store.
Arginine and taurine. These aminoacids help repair muscle tissue. Weight lifters use them all the time.
DMG. It is a precursor to immunoacids and supports collagen production.
Silica. It helps in the production of the collagen fiber. It will make you hair grow thicker and faster. It also helps repair the skin. Many skin creams have silica.
I suggest no exercise until the muscle inflamation is completely gone. Mild stretching is all I would do. Exercise will direct blood flow to the damage muscle, causing more inflamation. Apply ice in bags to the area. With anti inflamatories, nutrition supplements, and no exercise, you may see results in a couple of months.
Your bed may also contribute to the problem. Memory foam beds and soft beds are not good for inflamed muscles. The memory foam fights you when you try to move, forcing your back to make a bigger effort. This is unnoticeable having a good back, but when your muscles are inflamed, it makes a big difference.