Bruno Bettelheim (A Good-Enough Parent, author) posited that most tantrums are caused by frustration. Perhaps it's a combination of his limited ability to communicate, or his upset that his ears are bothering him.
I can't say.
One therapy you might try is making cards that have words which might be important to him. You will actually have to use pictures of these objects on the cards (one card per picture) and work with him to help him become familiar with them. You can have cards for food (draw a picture of his bowl and spoon), cup/drink, diaper, hugs, sleep, books, etc. In short, a small vocabulary that is relevant to him. Teach him to present the cards to you when he wants to convey his needs, and when you think he is needing something, bring out the cards. Talk to him and point to them. Bring them out when he's upset and ask him show you what he wants. It'll be a lot of trial and error at first, as he discovers what each card truly means, but if this ends up being an effective method for him, he'll keep at it. If your son is hard of hearing, a visual way of communicating can help. Be sure to draw his ears, too, and hold them up to him looking into a mirror, so he can understand what the illustration is supposed to be. (If you don't like your own drawing, use pictures from other sources. Online, we can find a lot of line-drawings, which is all you need for kids. Just paste the picture onto cardstock.)
I hope you discover what's troubling your little guy. It's so hard when we have limited communication.
H.