age!
i personally have never used a shoulder rest and don’t like them. i will give them to some of my students when i feel they need them but i have always tried to avoid using them and here’s why.: the shoulder rest raises the violin up so that it it vibrates more and makes more tone. one would think that this is an advantage but many years ago my daughter was practicing many hours a day when she was in conservatory and was having a ringing sound in her left ear that lasted for hours after she finished practicing, not a good sign. of course we were very worried and 