Suppose I have an account from San Francisco and I access the account from Boston. Will that be a problem? I mean what if I create an account from one state in US and acess that account from another state.
I assume you mean Paypal. Well, it should not matter. Paypal does not restrict you to stay on your own state and people in the US travelling to other towns and cities are common activities with the technological advancement in transport particularly planes and rails. However, you should be able to provide evidences that you are actually in the US when using the account there. So if you are migrating to the US then it would be fine to set up a US based account and sign up with your home address and still be able to commute to some other states and use the account. If you are however planning to circumvent the rules by setting up a US Paypal account while still residing in Nepal, I would say that is not a wise thing to do. It would indeed hurt your credibility with Paypal and goes against the terms.
Shouldn't be a major problem. If you appear to have simultaneous access from both the states, you might need to submit proof for your account. If it is simply the case of a business trip, you can inform them via e-mail if you want.
I dont think its an issue if you are trying to access your paypal account from other state of the same country. However if you are moving from one country to another country's state then that is certainly a reason for creating an issue.