Hi Brenda,
Welcome to the site.

Pain is actually a good sign - usually that of an infection. Many of us with late staged cancers have had no pain symptom at all. If you have something like PTA (PeriTonsillar Absess) for instance, it is very difficult to treat with antibiotics (it requires a long term antibiotic treatment plan). PTA could give you all of the symptoms you describe.

CT's are incomplete data. The "swelling" could be anything. "Swelling" often times simply means that the anatomy is not symetrical on the scan. Usually this is done with a comparison to a previous or baseline scan or simply comparing the affected side to the unaffected side.

The "direct visualization" exam is more important (at least that's what my head & neck surgeon told me). Don't fear the scope, it's really not a big deal. They spray a little numbing agent and there is no pain before or after.

I don't believe that, generally, oral cancer is passed genetically, it's typically caused by environmental reasons Like using tobacco or exposure to other irritating substances, like alcohol or drugs.

It's great that you are on top of this. Better to get an accurate diagnosis now while it's highly treatable. Be sure to let us know what the outcome is.