Instruments place specific demands on our bodies. Often, many hours of practicing every day, as well as static positions lead to long-term health impairments via tension and stiffening of the musculoskeletal system, if no targeted compensatory training is undertaken. Musicians always get problems exactly where they don't need it.
Experience a new posture at the instrument in which the body's own energy flow can be maintained, and how small changes in the handling of the instrument can possibly bring about big changes in your playing.