The roof of my mouth itches so do my gum. what could be happening in my mouth?

Allergic reaction: Could be an allergic reaction to food or mouthwash.

Itching: Could be from overly agressive brushing, trauma, systemic disease, bacterial/virul/fungal disease, burn, etc. Most probable cause, however, is allergic reaction to food, dentifrice, mouthwash, medication, or something environmental. See both your Dentist an an Allergist.