Does this help:
- In your Shopify Admin Panel, go to Settings / Shipping
- Scroll down to where the country is United States (with a US flag icon preceding it)
- Right below it, you will see your Shipping Method which is a hyperlink. Click on it
- Scroll down just a little, and you will see checkboxes for each state
- Save your changes
If you have more questions or if that didn't work, let me know and I could show you via screen sharing.