Two Days Ago I Had Soreness Under My Right Armpit.

Two days ago I had soreness under my right armpit. The next night I had a sensation like someone with an iced glove came and put their hand on my head behind my right ear. The next day I have a swollen pocket that is over my clavicle on the right side. someone said it looked like swollen lymph nodes. Should I be concerned. I have not been sick otherwise.