Irritation in horse's ears anyone?

Horse has got progressively grumpier over last few days. Yesterday whilst out there was head shaking and a definite uncomfortable response when her ears were touched. More so than usual. She also launched herself at Sid with teeth gnashing and very nearly got him twice with a well aimed kick. Today she's tried to bite me and almost succeeded. She's always been a grump but this is well over her usual level. Any ideas? Been to horse shop and they had nothing. Will be in contact with vet on Monday.