How do you get the 'clicks' out of your neck and shoulders?

I do feel really tense because my neck and shoulders are really tight and my neck clicks everytime I move it. The click sounds ‘great’ but doesnt actually seem to get rid of the tension. Are the clicks related to the release of tension or are they just sort of sound effects? Why do our joints click – like clicky knees etc.

Just wondering – oh yea and any advice to get rid of tense shoulders and neck myself (nobody on hand to help!)