One of our children has joint pain issues, and they seem to be greatly worsened by gluten exposures. She has been gluten free for most of her life. She presented with horrible joint issues following prolonged, chronic exposures at school that resulted in chronic, painful skin rashes. Her first hospitalization resulted in testing for several tick-borne diseases. In her second hospitalization (it was immobilizing and sometimes roving joint pain - the hospitalisations were due to severe joint pain that settled in her hip leaving her unable to walk - different hip each time). The second hospitalization put us in with a rheumatologist that agreed strict gluten elimination seemed most effective for her. Eventually, the schools became more accommodating, and the rashes and joint pain abated. We have since gone to another rheumatologist for a check-up on her progress, as we were overdue for rheumatologist follow-up. He explained that she has joint hypermobility that lends itself to easy injury, and he also believes that gluten making it worse is a very likely and understandable issue. He is helping us to address some of the things that we can do to help her manage the joint hypermobility condition.
So, all that to share our experiences and suggest that in addition to a gluten connection, you may also want to consider tick-borne diseases and joint hypermobility syndromes.
Someday, I want to spend some time researching the joint hypermobility issues. I want to understand if joint hypermobility is related to connective tissue disorders and understand if those are likely presentations of celiac/gluten issues.