Hello,
Bad breath aka Halitosis can present due to intraoral or extraoral causes.
Generally, periodontitis, periocoronitis or poor oral hygiene all can lead to bad breath.
Extra oral cause could be chronic tonsillitis and siniusitis. GI disorders also cause halitosis.
Next Steps
Consult a dentist for a general check up to reflect on your oral hygiene.
Health Tips
Given your history, ruling out other medical comorbidities, we need to address the source. Consider tonsillectomy after consulting a physician.