from across the Pacific Ocean? They would not have used the word Pacific since that name is European based. So how would we know that their origin stories refer to the Pacific? They lived in the East in the 1600s near the Atlantic coast and were driven westward into parts of western PA, Ohio, Virginia and West Virginia by other tribal nations and by European settlers. Over the years, they became split up and spread out to parts of the Midwest and the South.
It would be quite rare for a people living so far away from the Pacific Ocean to carry a unified cultural identity and stories of Pacific origins for over 20,000 years. The original people in the Americas did not have the languages and tribal identities that they evolved into over the centuries and millennia since the first humans arrived in the Americas.
There is an origin story among the Shawnee of coming from an island composed of the back of a turtle surrounded by water. But the story does not say where the island was located. It's an origin concept that exists among other Native Americans and the source of the term Turtle Island for America. That refers to some shared images in creation stories among various Native cultures. The Haudenosaunee (Iroquois) also call America Turtle Island, based on religious stories of the creation of the world. But the Shawnee are an Algonquin culture, not Haudenosaunee.
Here is the Shawnee story about origins on an island.
https://indigenouspeoplenet.wordpress.com/2022/08/19/mythologies-of-the-shawnee/#:~:text=The%20Shawnee%20creation%20myth%20is,and%20traveled%20to%20this%20one.