Find a top ENT who deals specifically with oral cancer. You are (unfortunately) not too young to have it - our youngest member was 18 when diagnosed and he - like many others here didn't have any precursors for it. I'm one of them. And frankly what you are saying rings very clearly with me - I had issues with my left oral tongue (at the back on the underside) this went n for some time - I saw an ENT - he biopsied it saying - well its all red, but I don't know here to take the biopsy from as its a large area. I had no lesion just a lump which he would have felt if he'd palpated. My biopsy came back inflamed tissue. He blew me of didn't even suggest a follow up. 18 mos later it became super painful (a step up from really painful). Another ENT biopsied it again. DX - oral cancer.

Please don't freak - this doesn't mean it's cancer, it could be major irritation for your reflux, but gdor your own mental ease you need a definitive DX either way. Do not let them blow you off. The demographics are changing for this disease,

Best of luck and let us know what happens.