Re: Lower back hurts bad...
Welcome to the board. Lower back pain is very common...to the point that almost all human beings experience it at some point. I assume your job at the furniture company involved lifting, so it is entirely possibly you have strained or caused a problem with a disc. This is the soft cushion between each pair of vertebrae in the spine that is subject to bulging or herniating. This can happen over time do to "wear and tear" or it can happen suddenly from an injury. Or it may be that you have a chronic muscle strain that was suddenly injured further.
The obvious quick answer is to go to a doctor, have x-rays and/or a MRI to see if something is damaged. However, I understand that you have no insurance, so this is probably not an option at the moment...so I am going to suggest that you stop the volleyball for a week or two and see if that helps. You can use ice or cold gel packs for pain, and whatever swelling that may be going on...but you'll need to do this on a regular schedule, several times per day to get much effect. Take over the counter NSAIDS if you tolerate them...and then do what you can to strengthen your back and core muscles. These two areas must be strengthened together as they work as a counter-balance. If one overpowers the other, it results in an imbalance that can lead to back issues.
If you aren't sure what to do, you can find some good books on proper care of the back and you can look online to find exercises and treatments for lower back pain. Look for a reputable site that is NOT trying to sell you a product. Do not waste your money on any product that promised a quick fix that you find on the internet.
And lastly, just be aware that back problems take a long time to get better -- even a pulled back muscle seems to take forever to feel better. Try to avoid repetitive bending, twisting at the waist, and avoid lifting heavy objects. Try to use good posture and body mechanics so you are not stressing the spine further. And try not to sit for longer than about an hour at a time -- get up and move around before you go back and resume sitting.