I can’t seem to get an ear on my sourdough bread. I bake them in a cast iron pot 13 quart. I feel like I am getting it tight when I shape it. As soon as I score the ear, it opens up wide.
Sounds like you're scoring too deep. Scoring works when everything comes together just so from the ferment to shaping. When scoring don't go too deep and score at a 45° angle. Look for videos on how to score and then it's just practice, practice and more practice.
could also be over-fermented.
see DanAyo's videos: www.youtube.com/channel/UC7mXjnPpTDoVJxRdrG3ZeYw/videos
Look for his videos about ears and oven spring in the title/description.
I think if it flattens right after you cut it is either over proved or not enough strength built in the dough. I found adding a few stretch and folds helped with that.