I find many girls want to progress to the straddle/straddle invert before having strong fan kicks. They rush to invert before they develop the strength. When you are strong enough to rely on your abs/core and arms and hip flexors, you can really stabilize the scapula so that you don’t ‘wrench’ yourself up by forcefully contracting the mid-back muscles on the side closest to the pole.
If you have already done this, I’d suggest deep tissue massage. And, another simple thing is to try and evaluate your sleep position. Sleeping on the affected side takes the scapula out of neutral alignment and further crunches up those rhomboid/infraspinal muscles that are in spasm. If you can sleep on your back, that will tremendously aid your healing.