What should I do if both tail lights won’t work but the brake lights do


Side Note- I went to change the tail light bulb but it didn’t need to be changed

 

Are there any other lights not working? If so, it sounds like a wiring harness issue. My (former) 2001 Accord had this issue, a squirrel decided the plastic in the wiring harness was tasty and chewed it up.

 

Front head lights work & brake lights work

 

Year, model, trim level would help.

 

Not trying to be a contrarian but I would double check if its a double filament.
in any case if both sides stopped working at the same time I would start by verifying the it even works by applying power as close to the bulb in the circuit as you can. Then trace your way back to the switch checking for shorts or damaged/burned wire.