My ear has been plugged for like four days and I tried to hold my nose and my breath but it hurts?

Needs evaluated. Best to have someone (doc, np or pa) and make sure you canal is not occluded with cerumen(wax) and evaulate your typanic membrane (middle ear).
Ear plugged. This sensation may be caused by obstruction in the canal (wax or foreign body), or more commonly, fluid behind the eardrum -- as treatment differs, this is best evaluated by your doctor.