The neutral grip (palms facing one another) is the best grip to use if overhead pressing exercises are bothering your shoulders.
With the elbows pointed slightly forward instead of straight out to the sides, press the dumbbells using a neutral grip. Bring the dumbbells close together at the top without touching them.
Most personal trainers couldn't pour piss out of a boot if the instructions were printed on the heel, so when it comes to squats and deadlifts, their advice is usually dead wrong.