Get rid of joint popping and cracking?!

I'm a fairly healthy 22 year old female. All my bones constantly crack (wrists, elbows, knees, ankles, back, neck, fingers, toes...everything...) My right knee had actually starting becoming really stiff and uncomfortable, especially sitting for long periods of time and not being able to move it. I've never had any injury to it. My doctor told me I was overweight, putting stress on my knees so I lost 40 pounds.....nothing changed. Everything still pops and cracks and my knee is still a little sore and stiff. I've been to a bunch of different doctors who told me it was all normal. Is there a way to help bones stop cracking so much? Specific exercises or supplements? Or is this an issue my doctors keep overlooking? I do take glucosamine but that doesn't seem to be making a difference.