Are there mobile roaming charges in USA among different states?
Most probably no. Of course to really answer the question you would have to know what service specifically you are talking about, but, as far as I know, nearly all the services offer free, unlimited calling from anywhere to anywhere in the US. There are a small number of low cost plans that are highly restrictive, but the restrictions are not for calling between states, but may limit the amount of calls overall you can place. At this point, nearly all smartphone plans include unlimited calls within the US, unlimited texts, and a specified amount of data. There are also a few plans for old fashioned feature phones (that do you access the internet) but I don't know much about them.