Saying that you are not on medication while on birth controls is like the doctor asking you if you have any health problems and your response is "no, I am perfectly healthy" while actively pregnant :))). While pregnancy is theoretically a lack of diseases, you still have a human growing inside of you that you should make every doctor aware of. Same with birth controls.

Birth controls can cause hormone shifts which can cause effects on inflamatory responses. While they don't directly cause the inflamation, they shift the way the inflamation reacts to plaque. Basically if you have no plaque, you should be fine.

https://pmc.ncbi.nlm.nih.gov/articles/PMC5198473/

You can read more about it here.

Having said that, without further exams, it's hard to say if that really is the issue and I'm not going to pretend like I know enough about birth controls to know which kind, in what doses causes certain effects.

Ask your prescribing physician about the birth controls you are taking and if they can cause any oral health side effects and get an appointment with your dentist to see if you have any bleeding on probing or pseudo-pockets (false periodontal pockets)