Agreed re your checking OA, after that, consider whether the changes in your thyroid hormones over the period may have temporarily affected your tendons. I have a separate condition which affects my ligaments, and therefore impacts on tendons, and the time before diagnosis of hypothyroid disease was agony, esp feet and knees, it all got better when thyroid hormones had been normalised for a while. Every time i have changes in thyroid hormones i know it - i am in lots of pain - esp knees and hips now, as well as feet - this may be because subtle tendon changes put more pressure on weak ligaments - in my case, exercise can't help and physios do not appear to know - I avoid them until my situation has been settled for months. i noticed recently
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3838329/. interesting other research also mentions tendon problems. Hope this helps