It's probably not cancer (though it could be almost anything, TBH). But I also wouldn't just brush it off. You want to go to the doctor with persistent problems like this if you can.
My mother had a persistent problem with her ear. Kept complaining it felt plugged up. Occasionally she'd go to the doctor and they'd give her antibiotics and send her home. She'd stop taking them and wait a while and go back to the doctor and they'd give her antibiotics again and send her home again. Eventually, whatever it was spread to her brain and she ended up in ICU and almost died. Apparently it became meningitis. Though we're still not really sure what the hell happened.
All we know for sure is that it started with plugged ear complaint and ended with almost dead and in the hospital for a month and bat**** crazy for almost a year after that before kinda sane behavior resumed.
Don't mess around. Go to the doctor. And make sure they understand this is a persistent problem. And be careful because they will probably try to write you off as a hypochondriac if you say one wrong word or they get the wrong idea. And if they do conclude that it's an infection and give you antibiotics, don't stop taking them early (not that most people would anyway). My mother seems to be convinced that medicine doesn't work and it almost cost her her life.