I've mentioned my neck problems on AB previously and have had NHS physio, acupuncture, anti-inflammatories etc.
The best things though have been spending less time on the computer (hard, I know), warm wheat sacks (thanks to fellow ABers for recommending this one!), massages and going to a chiropractor (far better than the physios, who basically said 'you're stressed - change job!')
The 'cracking' sounds are not dangerous, just a sign of your muscles being tensed up.
Most important thing, though, is to keep it moving - keeping still just makes the pain and stiffness worse. Yoga and Pilates are good for loosening up.
Hope you feel better soon...