I had this worry a month back, under my jaw close to my ear, swollen.. Rock solid...not moveable.
I freaked out! Especially when you google!
Doctor examined it and said there was one on the other side the exact same which was a positive thing. He also said don't use google! Mine were the typical 'bad ones' yet he was not remotely concerned and he's an ent specialist. He even said mine would never go back down... Apparently sometimes the flare up to fight an infection even if we don't feel any symptoms, means they've done there job.
Only be concerned if they grow and keep growing.
It's worth having the doc have a feel to put your mind at ease though, btw if you've been poking them they will grow in response to that! So don't touch! Xxx