Retainers are supposed to be worn for 2 years after removing the braces and then you can wear those just at night. A little shift must have happened in the last 2 years, that’s why they feel tight. You can check with your Pre op pictures, and see if the alignment is still the same or not.
Next Steps
Consult an Orthodontist.
Health Tips
Do not wear your old retainer, as they will be uncomfortable and tight.