E-commerce business. Do I need to register my company in every state I sell my products?

No. Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.

No. You only need register in the state(s) where you are "doing business" as that term is defined by each state. CA's definition is “entering into repeated and successive transactions of its business in this state, other than interstate or foreign commerce”. (Please see "Doing Business in CA? Be Sure to Register" at http://dana.sh/aQUtLS.) Your company meets that definition, and you registered in CA by forming your corporation here. It appears that you are not "doing business" in any other state. Disclaimer: This post does not constitute legal advice and does not establish an attorney-client relationship.