Tooth brushing aggressively and frequent usage of acidic beverages can all contribute to sensitivity in teeth due to wearing off of the tooth structure. Also receding gums can expose roots causing sensitivity or tooth caries going deeper can cause same effect.
Next Steps
Learn from a dentist the proper way to brush or search online for video tutorials. Visit a dentist. And pastes made for sensitivity work better if you use it like ointment on sensitive areas. Apply a little and let it stay there for 5-10 minutes before you brush and wash it off. So This is better don’t additional to regular brushing. Brushing and rinsing does not give these special tooth pastes adequate time of contact.