Oh god, no. I have never ever noticed anyone clicking while they walk, or indeed the constant clicking described above. If someone couldn’t help do it, or if it hurt if they didn’t, then their health takes priority.
What I’ve always disliked is the people who seemed to do it now and again, as a hobby. My son does it now and again, with his toes, YUUUK. Having read these posts I asked him if he clicked because his body hurts. He said no, his body doesn’t hurt. That’s the difference!
Op needs to ask colleague if he’s in pain and if the answer is yes, she needs to get headphones to muffle him out. Otoh if he is clicking for fun, or out of habit, like my son. Then colleague needs to be told to stop! But the fact that he does it all the bloody time suggests he has to?
Talking of pain v no pain, one of my mates as a kid used to click. At that age, I thought it was quite cool, and asked her how she did it. She didn’t mention any pain either, so I had no idea of the pain element. I remember trying to click (but I couldn’t) and my mother going nuts and saying not to click, since it made it wld lead to a habit. This is clearly wrong, at least for those posters with bone pain. Probably my visceral hatred of clicking comes from my mums dramatic reaction.
Maybe the girl on the train, who was loudly cracking her fingers, was also in pain. I don’t know. It was the equivalent of retching. Really grating. She was very pretty, very young, and her mates didn’t seem to notice.