So after trying to figure out which movements hurt and writing that whole description down, I think maybe it's not impingement after all, but maybe I just pulled either the anterior deltoid or the coracobrachialis. Does that seem right?
I went and got a massage today from an actual masseuse and it was brutal. There was some spots she would touch around the front of my shoulder that were really, really painful. It feels a little better now to move around, but when I touch where she was pushing on it, it feels tender in a different way, like more generalized and with less pressure required for me to notice the tenderness.