Hi Justme, inflammation is a funny thing no rhyme or reason as to why it flares in a particular area. I'd say you've developed a weakness in that area from having costo before. Talk to the physio about
it, they helped me greatly while I was recovering to help build muscle strength again and balance. Spent a lot of time balancing to strengthen core muscles. If still really sore go for the cortisone injections, it was the only thing that settled me, plus a big whack of prednisone, awful but it worked. Goodluck. (I'd had pneumonia and then had to come off my humira and methotrexate so I could fight the disease, I flared terribly, massive inflammation everywhere but the ribs were horrendous, really hurt to breathe let alone cough)