Knee replacement was done 2006 but now getting pain and clicking in it. is this in it's way out and i need another replacement done? i'm 54 yrs old.

Possibly: Have an orthopedist reevaluate the knee. These symptoms may suggest loosening of a component of the prosthesis.

It probably isn't as: its only been there for 7-8 yrs. You do need to have it seen to, & XR's and some lab work done; and may be some scans as well. to make the correct Dx, before one can say whether you need a Revision or not. Meanwhile use a Cane while ambulating and do the exercises you were shown after your surgery, as they most likely would do no harm, but strengthen the muscles & reduce your pain even. Get Seen.