Question
I've been very curious about this.  I started to experience soreness in my upper back, left side, that I attributed to sitting in the same position for too long while typing for long hours (transcribing documents all day).  I then started to experience a tightness in my chest, also on the left side, just above the upper outer part of my left breast and extending to directly above the breast.  This worried me a bit, even though I had no other symptoms such as shortness of breath, fatigue, dizziness or anything.  But it certainly seemed related to the shoulderblade/back pain and felt like a muscle tightness. The only difference was when I pressed on the area on my back it felt tender and when I pressed on the area on my chest it did not.  

Last night I felt sort of a knot in my back where the pain was.  I started massaging it, and suddenly the pain in my chest subsided.  Today I sat in a car (passenger seat)for an extended period and the back pain returned, and shortly after my chest began to feel tight again as well.

If I take two fingers and press really hard against the tender spot on my back, it seems to temporarily alleviate the pain in both my back and chest.  Is there a muscle that can be felt in both the back and chest, and could sitting poorly for just a day or two cause a very bad muscle strain?  (my keyboard was too high and my shoulders were hunched a bit, and the mouse was too far over the the right so I rotated that way every time I used it, which was often.  Also I did not have a very good support for my back the whole time.  I have ordered some special equipment to be sure this doesn't happen again!)

Answer
Hi, Tanya,

You've just described how tension patterns form:  repetitive use in poor position.  We become how we live.

The ribs go back-to-front.  Tension in the back is communicated to the front to hold the rib in place (prevent rotation).

There's an article, Addressing the Human Factor in Ergonomic Solutions at somatics.com/page4b.htm

with regard,
Lawrence Gold