Hi Jeannie: As a Catholic, I can relate to the sore knees. I also have some trouble just balancing when it's time to stand. I tend to alternate sitting and standing and it helps, and I reserve the kneeling for only specific parts of the Mass.
Yes, thinking back to my grade school years, I remember little things like my finger and thumb muscles getting really sore just holding into something. And, I've gotten toe/leg cramps off and on for years. My neurologist asked me if I had "always been klutzy" (nothing like being blunt, eh??) and the answer is, yes. Guess that's why I always hated P.E. and any sports. The pieces fit, that's for sure.