Our little guy really liked to rub stuff in his feathers when he was that age... Especially his head feathers. He would self-scritch with whatever he found (that I left for him) in his cage. And sometimes even made up his own games. I once found him with his foot wrapped around his own head and the toenail of his short toe in his own ear hole, very gently moving up and down. No idea why he did it, but it makes me wonder if your Echo might have gotten something stuck in his ear.
If he lets you do deep face pets, you could check during a good scritching. When he is relaxed, and without using force, gently part the slightly thinner hint-o-yellow feathers that cover his ears. If he pulls away and won't let you look at one side or you notice him scratching at one side of his face more then the other, that might be the issue. At that point, a good avian vet might be your best bet since most people don't have the tools or skills to pull out something wedged between those delicate face bones.
Is anything coming out of his mouth when he shakes his head? If so, he may be vomiting. That is an urgent issue and it's certainly time to get him to someone who can diagnose and help you correct whatever is wrong.
Keep us posted on how Echo is doing!