I had thyroid cancer 2 years ago. just had ultrasound which showed 7mm node. is it possible if it is cancer a cancer other than thyroid ? like throat?

See your doc: Most likely a benign inflmmatory node or recurrent thyroid cancer (definitely curable!) throat cancer possible but much less likely. Talk it over with your doc.

Yes: To determine if it is thyriod cancer, you need a tsh-stimulated rai total body scan if it lights up , it is thyroid tisse if it doesn't ' light up' it could be a local growth , like a lymph nore, or from throat cancer see your surgeon or endocrinologist.