If your sales are conducted from your presence here in the US you must pay taxes on the gain and you must have a SSN or FEIN to file taxes. You need a CPA at a minimum. You need a good customs broker at a minimum. If you want to do business under a name not your own you need a fictitious business name statement. You may need a local business license. There may be local and/or state taxes to pay on gain or on sales.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.