Well, it turns out that although the pain is under my ribcage, the cause of it is a uterine fibroid. It must be pressing on a nerve that runs along the side of my torso or something!
Because of logistics, I won’t have surgery to remove it until September 29; I have painkillers for when it gets bad in the interim.
Thank God it’s not something worse and thank you all so much for your prayers!! I’ll need 'em again when I have surgery, of course.