In the same vein of the trigger point therapy I found that playing and manipulating your fingers around the side and inparticular the back (directly behind where the collarbone stops and the shoulder begins) works wonders. I had a similar case where I aggravated it from snatches and power cleans, I found the initiall sore spot in the muscle that overlaps the back of the shoulder to the front around the side of the shoulder (if that makes specific medical sense) I then rubbed the #@$% out of it, so hard that the next day it would feel as though I had been hit - hard - in that specific spot. I feel by potentially rupturing whatever blackage was there it definately helped with the flow and overnight success was achieved. The very same thing was used for my elbow injury which was an "itis" thing, every night I would rub the crap out of it with my knuckles until it felt good and "bruised" so much so that I would really feel it the next day, then and now the pain has gone.
I will also add one note, Dont forget that there are major linkages to the muscles and what seems like a straightforward pain is actually linked to the muscle further down the line
ie: my shoulder stopped responding to the one point that alleviated the pain, one night playing around on a roller I hit a spot half way down my back almost in the centre and almost past the shoulder. When i hit that spot a tingle went straight through the sore point into my shoulder ,down through my elbow (where the "itis" pain was) and into my little fingers. That's my new toy at the moment which allows me to feel better and less pain about pushing people of me in BJJ and alround ME and Metcon days......
Very cool stuff, play with it and if you find a spot that hurts make it hurt more - pains a good thing