You just need to get your spine back in alignment. Someone as young as you should not be having joint problems, so it's probably not that. Check out egoscue.com.
There are exercises on his site you can do, plus buy his book and or DVD.(i have both I bought at amazon) I have issues with pain way too much, plus the snapping, crackling and popping..and it's my posture from carrying around so much weight for far too long.
Pete Egoscue's exercises help people of all ages, some people have had pain or discomfort all their lives and do the exercises and the pain is gone. They are shocked. I know I was when I finally managed to do some of them.
Someone on this site mentioned it awhile back and it was one of the best things I've read in a long while. Really helps. Try it. The most you will lose is your cracking and snapping.