Uneven shoulders during sun salutations - help a yogi out!

Kia ora, fellow wellness warriors! This Kiwi adventurer needs some yoga advice. During my sunrise practice, I filmed my sun salutations and noticed my shoulders are totally out of whack. One's stable as a mountain, while the other's retracting like it's trying to escape to the bush! I've tried to correct it, but both shoulders feel the same to me - about as balanced as my kombucha to coffee ratio (which is to say, not at all). Any tips on what I should focus on to sort this out? Internal cues? Exercises? I'm open to anything that doesn't involve giving up my crunchy peanut butter. I've attached a cheeky pic in my yoga shorts to show what I mean. Don't worry, it's SFW - no full Kiwi on display! [Image link] Edit: Dr. Google suggests it could be a weak serratus anterior. Anyone know if strengthening this would help get me back to yoga zen? Namaste for any advice!