My sister complained of similar problems when she started getting into shooting her carry pistol regularly.
In addition to the advice about leaning foward in your shooting stance, I would advise also doing some stretches before shooting, as you would before any physical activity. And some stretching afterwards as part of a cool down.
NRA Life Member
Me: "The .45 GAP was an answer to the question nobody asked."
Trooper pal: "Says the guy who thinks .38 Super and 10mm are viable pistol calibers and gets mad when Wal-Mart doesn't have them."