@MikeMason-- The ears, eyes, nose and throat are all connected. So an infection in any of these can easily cause symptoms in others.
A headache behind the ears is usually caused by a sinus infection or a migraine. Ear infections can definitely cause severe headaches and I don't think that vertigo has to be present for it. Ear infections can also cause eye and jaw pain on the same side of the face.
You should see an ENT specialist to check for infections. It's also possible that you don't have an ear infection anymore, but the previous infection caused a change in your inner ear pressure which is giving you headaches. Even antibiotics can cause ear pressure change and symptoms like nausea, dizziness and headaches.