It sounds 100% normal. Everyone who's ever owned a puppy and not done foundational work when it was younger has experienced this when they enter adolescence -- puppy exuberance to play with the emerging brattiness and energy of adolescence.
Many first-time owners seem to expect that well-behaved, obedient German Shepherds spring into the world already formed, like Athena from the head of Zeus. It doesn't work like that. Those well-behaved dogs you've likely seen and wished for are the product of great owners who put in the time and have the patience to work with their dog, build a bond, and shape behavior effectively.
Stop doing silly intimidation tactics, shouting, and alpha rolls. That is a long-discredited training method that just leads to further problems -- as you're experiencing. This age and its issues are the why so many German Shepherds end up surrendered in American shelters and finding its way to breed rescue -- most of them are dumped at 6-18 months old!
Please sign up for an excellent obedience training class ASAP with a great trainer -- group or private lessons, depending on your means, just get moving on training. The class isn't for the dog, it's for the human to learn to communicate and work with the dog productively. Once you learn how to do that, you can help the dog learn anything you want without yelling, pinning it, or otherwise getting upset. This situation will only get worse until you build the skills to work with your dog effectively, teach replacement behaviors, and get active building foundational obedience skills (which can be GAMES that you play every day together, from the dog's perspective).