Right now the pain seems limited to certain movements and when breathing in and is localized under the lower portion of my lats, so I'm thinking exactly what you are thinking: serratus posterior superior.
Back in high school I pulled the serratus anterior and it hurt like something was stabbing me every time I took a breath in and my parents took me to the doctor at hospital (I would've resisted but I couldn't take more than 1/4 breaths). The nurse wasn't exactly schooled in sports medicine, but prescribed a muscle relaxer and pain killer. Normally I hate these things, but not being able to breath wasn't fun either. The pain killer did absolutely nothing, but the muscle relaxer allowed my muscles to chill out, and I was able to just lay low for a few days and felt better. Since then I've now pulled all three different groups, but nothing as severe as the first time.
Please don't think I'm disregarding your advice as it is much appreciated; I've had several friends that have had great experiences with seeing chiropractors with their back pain. It's just that with my schedule it's very hard to get time off regularly, especially since the injury is non work related, and my work hours run all over doctor's hours. I've had major pulls of what I'm assuming is a part of the erector spinae, and that hurt like mad for 2 weeks, and was off/on for about 5 - 6 months. If I ever experience pain like that again I will see a chiropractor, but for now I'm just going to work around the pain.