Originally I am from Michigan, so I say Pop. Now I live in Georgia and everyone says Soda. (It's also the home of Coca-Cola Corp. so a double whammy to the Pop people.)
The reality is Pop and Soda are both abbreviated versions of the longer original term Soda Pop. So everybody is correct. Except for those who say Coke. That is just wrong and you should be ashamed of yourselves.