Gum recession can happen for a few reasons.
1. Aggressive brushing
Brushing vigorously can damage and push the gum which causes the root of the tooth to be exposed and in the long run, that will lead to tooth sensitivity.
2. Periodontal Disease (Gum Disease)
Gum disease causes gum inflammation and if left untreated, it will lead to gum and bone loss.
3. Poor Oral Hygiene
Inadequate dental care which includes poor brushing habits, lack of using dental floss and infrequent visit to the dentist makes it easier for plaque to turn into calculus which requires professional cleaning by the dentist to remove it.
I would advise you to see a dentist for dental examination to find out the cause for your gum recession. Your dentist will be able to find out the cause of your gum recession and advise you on the next course of action to take to prevent your gum from further recession.
