Adam's Apple lump

Hi there,

I have a lump firmly sitting on top of the left side of my adam's apple, it moves with the adam's apple like it is part of it. The right side is perfectly straight with no lumps or bumps.

I went to the clinic and the clinic doctor didnt really probe the lump at all... felt around it more than anything and told me he thinks it is a lymph node and gave me a potent antibiotic to take for a week and sent in a form to the hospital to get an ultrasound done on it...

What will an ultrasound tell him? and does it sound like something to worry about?