Toothache, but not when chewing

Hi! I have a toothache on an upper molar tooth since yesterday. The funny thing is, I can load the tooth normally and bite it hard without the pain getting worse. I have the feeling that the cause lies exactly between two teeth. The last time I cleaned with dental floss, the initial slight pull on the tooth suddenly caused severe pain. Could it be that it is not the tooth that is affected, but the gums? I think I’ll go to the dentist tomorrow, just want to know what I might have to adjust to.