That is one cause or weakness in the bone joints. The type of bunion caused by tight fitting shoes is soft tissue issue. on mine the bone is missaligned and rotated. When I first noticed it in 2002 I went to the doc and he said its nothing don't worry about it. Well its gotten worse. I now where inserts and have the specter of having to have surgery to correct the issue. The big term in Hallux Valgus, its pretty painful to run.
Pretty sure if they had given me inserts in 2002 I would be better off today. Oh well!!