My ribs hurt after a night out on the town, what could it be?

I went out to a bar on Saturday night (three nights ago), I was pretty much on the low end of drunk that night. Not enough to be an idiot, but definitely more than tipsy. When I woke up the next day my ribs hurt on the lower left side of my body and nowhere else.

The pain is similar to gas, but not as sharp, it’s more of a sharp ache. The area is about the size of my hand/palm and hurts mainly when I apply direct pressure, hunch over, stretch as far as I can backwards or lay on that area. Over the course of the night I suffered no trauma to the area and spent the night in a big fluffy bed, not on a floor. There is also some soreness between my shoulder blades, and it seems easier to ‘crack’ my back while stretching in that area which is normal when I’m sore somewhere.

I’m not particularly worried, as I remember something similar happening last year, but I am curious as to what it could be.

Any ideas, Fluther geniuses?

This is a diagram! Oooh! Aaah!