Hanging from a bar can help stretch things out, but I’d say take it slow—don’t push too hard too soon. Seven hours is pretty intense, you might want to dial it back a bit. If the pain is in your left shoulder blade, it could be from muscle strain or poor posture. It’s awesome you’re trying hanging, though! Just build up gradually to avoid overdoing it. Also, you might want to try some
natural steroids, like those found in foods that can help with recovery and muscle repair. I’ve heard some people have good luck with them. Resting and stretching are key, too. Maybe a gentle massage to release the tension?