Should i be concerned if i discovered a lump under my tongue. could this be cancer?

See a doc: I would suggest you see a physician, preferably an ent, asap. I don't usually advise people to get worried or too concerned but if that's the only way to make you see one, please be concerned.

Unknown: Personally, I am always concerned of the unknown. Until you are examined locally by an oral surgeon, we don't know what that lump is. It may be absolutely nothing, or it might be more serious. Until we know what it is, there is concern. That's why you need to call for an appointment.

Lump under tongue: This would have to be seen in person. It may be normal anatomy, something benign, or less likely but possible something more serious. See your general dentist or an oral surgeon to find out for sure.