The short answer to this question is probably "Yes." Most states have some business licensing requirements governing any for profit operation. Fortunately, a business license is inexpensive and simple to obtain.
While certain details may differ based on business location, generally speaking the steps to getting a business license are:
1) Complete a business license application. Filing a business license application generally involves going down to City Hall and filling out a form (or forms) that details the business being operated. The forms will ask who the business owner is (you), estimated profits the business will make in its first year (give the best educated guess possible), and other pertinent information.
2) Request a DBA. A DBA ("Doing Business As") is your business name, also known in many states as a "Fictitious Business Name." Generally, a DBA request can be filed at the nearest county court house or records building, but first, you've got to check to make sure that there isn't someone else using it. Checking for a business name can be easily accomplished with the county clerk.
3) Publish the business name chosen. This means putting an announcement in the newspaper, and is required in order to legitimize your DBA. This is pretty much an automated process; all that's really required is to pay the fee and the newspaper will do the rest.
Tip: Smaller papers often charge less than larger ones.
4) Once these steps are completed, it will likely be required to apply for a seller's permit, establish an Employer Identification Number, and register with the Board of Equalization so the business can collect & pay sales tax. In addition, the particular state or county where the business is being operated may have additional zoning laws, permits, and license requirements.
The safest way to ensure that all the bases are covered is to visit the local chapter of non-profit, small business advisory organizations SCORE or SBDC, for detailed guidebooks on licensing requirements in your state.
Related Resource: State Business License Resources