Hi Blair_38,
Thanks for posting your concern.
I'm sorry to hear about your issue editing transactions. There are a couple of possible reasons why you can't edit transactions. I suggest first opening the Setup > Preferences > Security tab window and making sure the two options in the screenshot are not marked check.
After this, please make sure that your user role from the Setup > User Access > User Roles tab window have read and write access to the inventory.
Let us know if you require any further assistance with this.
Thanks,
Genreve