Sorry for digging out old thread but currently i'm facing kinda same situation as yours where i have cyst underneath my molars (big tooth) behind which pressure down my wisdom tooth.

Not sure how long it developed d but i first noticed my jaw has this minor bony protrusion (and did not seek for dentist check) and seek for general doc roughly 3 years ago.
The general doc done me X-ray and CT scanning but did not notice any abnormal.

Between these 3 years i also done some oral and tooth checking with x-ray but non of the doc realised

Time forward to last month when i went for dentist to fix my upper molar, the doc (differ with previous) done another round of x-ray & saw there is this big black zone above my left wisdom tooth which now she refer me to gov hospital.

Whole the while i don't really feel anything actually.
But this week starting to like feel minor pain or some weird feeling - not sure is it due to stress
Next week will back to GH and consult again for surgeric appointment.

May i know that how you find out yours and was it big?
My case seems to be big and GH doc says my jaw has weakened and might facing fracture during operation. i might also need to remove two of my molars in order to access the cyst as well as wisdom tooth below it.