pain in chest, lower armpit, and ribs

[niftyzero]

i worked out last weekend and played basketball with some friends and strained and moved more that i usually do.

i've noticed within the last three to four days my upper chest and ribs on my left side(the side i use the least)aches a good bit. my left side aches from my chest ribs(side and under the left chest)almost up to my armpit.  

i notice it hurts pretty bad when i'm standing and bend down or hunch over.  Also it aches when i'm standing and take in a deep breath or laugh pretty hard.

if i am sitting or laying down, i can hardly notice anything but some mild aches in that region - and deep breaths in do not hurt either while laying or sitting comforatbly.

i'm under the impression that this pull or inflamed muscle(s)?

any advice would be greatly appreciated

[National Jewish Health]

Your symptoms do suggest strain of either muscle or intercostal ligaments between the ribs.  With rest, this will resolve spontaneously.  The use of an anti-inflammatory drug may hasten the healing.  Another, much less likely possibility, is that you may have strained the large nerve bundle that runs through your armpit and sends branches to your arm and chest, called the brachial plexus.  Once again, this should eventually resolve spontaneously, in about 10 to 14 days.