Pain in back when breathing?

Question

When I start to run, or play squash, I get this pain on the left side of my upper back every time I breath. Should I be worried?

Answer 1

It could be gas.  I get that too, sometimes,when I work out.  I've noticed that it's worse when I drink gatorade.  So, I don't do that anymore.  

Answer 2

I had the exact same symptoms before, in fact, they come back ever so often.  Doc. told me it was due to a strained muscle.  It hurt every time I took a deep breath.  Sorry.