Oh this thread has made me feel better. My DS has a lump on the side of his neck under his ear just like you have described. Squishy and about walnut sized.
My GP is a bit perplexed by it but seems to think it is an infected node or gland.
He has had a few sore throats over the last few weeks so he put him on a course of antibiotics to see if it would reduce it.
I think it has a little, but it is still there after a week on antibiotics so this morning he said to finish the medicine and come back in two weeks and he will ultrasound it if its still there.
So after reading your posts and updates I feel a bit better about the whole thing.
I was going to go to another Dr to see if they thought the same thing but think now I will wait to see if it goes down or get an ultrasound done on it.
Thank you Corelly