It's quite common for a nerve in the ear to act up. With me, it feels like there's a hair tickling the inside of my right ear. I found that if I wet the end of my little finger and rub it round the earhole the tickle goes away for several hours. Google for 'tickle in ear canal' - loads of links
The phrase about having "a flea in one's ear", where it originated in French, meant to be randy! In English today, of course, it means one has had a real telling-off.
In the past, when lack of hygiene meant people often DID get a flea in their ears, the standard treatment was exactly what Maggie says...oil poured in, which drowned the wretched creature.