Yes. If you're a US person or a US citizen living abroad, you pay income tax in all of your income wherever it is earned. And even most states claim this too. If you live in Colorado and travel one time to earn a consulting fee in New York you must pay New York state income tax on the money earned in New York, and claim it as a credit with Colorado. That means filing IRS forms, Colorado income tax forms, and New York income tax forms.

It's such a bureaucratic clusterfuck for a small business or consultant.