Shoulders are always a tricky one. Not just for golf, but also for general fitness. They are a finicky joint, and one that many of us have issues with. One major issue is compensation by the traps, or “shrugging” the shoulders when doing shoulder exercises. This leads to poor mechanics and knots in the upper neck.
The side lying lateral raise helps take the compensation out. Use an angle of 35-45 degrees. Don’t quite lower the weight all the way, nor raise it all the way up. Always keep the weight engaged. Use lighter weights than you think. It really isolates the delt, so it will be a bit harder than a normal lateral raise.