I would be very careful before doing stuff on your own. Every self help book, posture exercise, ergonomic setup, yadda yadda yadda ONLY MADE THINGS WORSE.

A good therapist who knows rib mobilization and myofacial release from the Inst. of Physical Art would be my first and only stop if I were a beginner. All the 101 things I tried and 101,000 dollars (slight exaggeration) were pointless.