I am 21 years old. I am not particularly active, meaning I do not exercise regularly, but I am not out of shape. My joints crack constantly in the following areas: back, wrists, ankles, toes, fingers, knuckles, shoulders, elbows, knees, hips. They do this on command as well as randomly throughout the day. I'm most concerned with my hips and shoulders. There is no pain. It is very loud and a little embarrassing at times. Is it harmful, since I am so young?