Experiencing Inner Ear Pain, Headache.

My son was previously diagnosed with Vertigo a couple of years ago. He is also taking Avamys spray for his sneezing allergy. From time to time, he experiences dizziness and is really sleepy for a few days then followed by headaches. He can't go to school for a week because of this. most recently, I gave him Vert and it seems to help but the occurrence of dizziness increased. When he got a bit better, we took him to an ENT doctor yesterday and said his health is perfect after checking his ears, nose, eyes and balance. He didn't give him anything. That night, my son is complaining about pain in his ear and had a fever until today. He throws up once. We are going to visit a different doctor later. But what could this be? I'm worried the doctor will say nothing again. Thanks!