It is amazing how many things affect our ability to have good breath support.
I have been going to a physical therapist lately because years of working bent
over a keyboard and drafting table have caused the muscles in my upper body
to be inflexible. To be able to expand those "hinged" rib bones to bring in
more air, the muscles need to be able to stretch and move. Mine are not in
the flexible, stretched condition they should be. Using breath support is
not only a technique to learn, but a physical conditioning ability that you
gain like an athlete. This needs a coach (voice teacher) who knows what
they are doing in order to assess your body and what has to be practiced and
trained. Voice lessons are not for everyone, of course, but if you want to
optimize your ability and get over blocks like tension and pain, lessons are
the way to go.

All the best,

Alice