Excellent Question!

You could look up some videos online or go get a massage and ask the therapist after they have worked on you what are the best stretches etc specifically for you and your body.

Getting a massage therapist that know a lot about neck and shoulder massage.

They could show you how to stretch or give you advice. You could get a massage from them and they could show you tips etc. I would call around to your local massage therapists and ask if they could help you with you learn
how to do so.

Good Luck!

Massaging and pin and stretching neck and peck muscles. Gently tug on your ears.