You might be having gingivitis.
Practice proper oral hygiene care habits.
Get teeth cleaning done from dentist every 6 months.
Next Steps
Visitil dentist for clinical examination and ultrasonic scaling.
Health Tips
"10 Dental Commandments for Happy Teeth!" by Dr.Rashmi Bamane - https://www.practo.com/healthfeed/10-dental-commandments-for-happy-teeth-40426/post