Bad breath or halitosis could be due to various reasons, systemic or local
Some of the reasons could be :
1. Poor oral hygiene, plaque accumulation and calculus
2. Intake of antihypertensive medications
3. Smoking
4. Xerostomia i.e. dry mouth
For poor oral hygiene, you can be advised to brush twice daily after meals and use a mouthwash daily for 2-3weeks and also go for a regular full mouth scaling in the gap of 8months-1year depending on your rate of deposits.
Next Steps
For swollen gums, it could be a reason of periodontitis which is inflammation of your gums, again due to poor maintenance of oral hygiene. You can be advised to rinse with lukewarm saline water, for now. Also antibiotics and anti-inflammatories could be recommended after clinical examination.
Health Tips
You should better consult a doc for the proper clinical examination and treatment plan.
Thank you, take care.