I had absolutely no sounds in my knees while squatting or anything else until I tore my meniscus. Now it clicks, doesn't hurt and isn't ever inflamed, there's no impingement in my movement at all, but I know for a fact that's my issue and it'll probably re-tear at some point in the future (such is the way of surgical repair).
Sometimes you can have tiny tears (ones that don't require any surgery to correct) that do require physical therapy, but often don't cause any symptoms. The physical therapy is easy shit, knee extensions & flexions mainly, with a stretch that 'unloads' the knee a couple of times a day. Especially if you're on your feet, lifting a lot.