Mine seem to go in cycles. I'm sure the doctor will ask you all of the smart questions about variations in your diet, exercise, rest, amount of walking and on what surfaces, any changes in footgear, and any minor injuries or pulls elsewhere (hips, feet, back, etc.) that could be causing you some kind of unhealthy compensation in how you move. Often what triggers mine is some other minor injury that's got me walking funny.
Glucosamine/Chondroitin has been a staple of mine for a long time, and overall I keep up with calcium and fish oil since I'm in my 40s. Otherwise I'm a believer in ice, ibuprofen and elevation...nothing you haven't been using for years, I'm sure.
Good luck.
Carl