Re: Back Pain: Bad Work chair?
Congrats on getting the situation resolved. A couple of things might be helpful. You should keep taking the ibuprofen, so long as you don't have any underlying stomach issues or discomfort. It will help with inflammation. You might consider icing the areas that are in pain. It will help with pain relief and resolving inflammation, as well. You should also stand up every 30 minutes, regardless of the comfort of the chair.
If your discomfort is primarily upper back, you should concentrate on a couple of things while sitting. First, make sure that your head rests above your shoulders, not craned forward. Second, keep your shoulders pulled back and avoid reaching forward for the keyboard/mouse. One of my PT exercises concentrated on pulling the shoulder blades simultaneously toward the spine to strengthen the muscles that keep the shoulders properly aligned.
If your pain is purely discomfort/tension, you can also self-massage by placing a couple of tennis balls between your back and a wall and rolling around on the tennis balls. Some folks do this lying on top of the tennis balls, but I find that standing and using a wall allows more control over the amount of pressure. This may help to work out some kinks, but don't do anything painful.
There are also some good resources; I think one is called Heal Your Back? Maybe some other folks can suggest specific resources for exercise.
If your back pain does not improve within ten days (sounds like it's getting better?) or if you have shooting pains in your arms/hands or loss of hand strength, seek medical attention.