My question is that my ear is paining me very much and also if am eating and brushing my teeth I also got pain in my ear. Please what's the cause of it?

Congestion or TMJ. It could be caused by a pressure buildup due to congestion in the eustachian tube. Or it could be caused by a problem in jaw joint. See your doctor for a diagnosis.
Get checked for. Infection in your ear and tmj/ inflammation of your jaw joint. Hope u feel better!