Is a dull pain ad the bak of tongue/top of throat indicative of a simple sore throat or strep?

Can be either one. Mild nose and throat symptoms can be from cold viruses, strep throat, allergies, etc... It can be difficult to tell what the cause is. If symptoms only last 1-2 days, it was likely allergies, irritation, or a mild cold. Doctors have rapid 5-minute tests for strep, so a primary care doctor can diagnose strep and start antibiotics "right away", which means within the first 3 days of strep symptoms.
I'm itself no. There is a big difference between a simple sore throat and strep. Your temperature, appearance and duration are important in diagnosing. Best to see your doctor since there is a difference in how you treat viral and bacterial sore throats .