What to do if i don't brush my teeth often i think its the cause :// if i brush them daily will gum disease go?

Brush often: Not brushing allows the bacteria in the mouth to adhere to the teeth. If not removed, the gums become infected. Minimally you should brush 2x/day and floss. If you already have gum disease, you need to have professional treatment to get your gums healthy. Consult with a dentist

Depends: If you just have the first stage of the disease (gingivitis) then good brushing and flossing can reverse that; but if it's the more serious gum disease, you may not be able to make it go away just by good home care. Please see a DDS.