When you say that you know the scales, do you mean that you know the pattern for playing the major scale on the bass? Do you know the numbers for the notes in the pattern and how to access them immediately? Your answer says where you are and helps with our responses. Speaking generally, though, you can play a great number of songs while yet staying in the box(the basic pattern). My advice to a new player is to stay in the box and get it thoroughly in your mind and under your fingers. Learn the sound of the intervals in the box. If I told you to play a 1,3,5,3, would you be able to play it? Many songs follow a 1-4-5 progression. Could you play a 1,3,5,3 on the 1, 4 and the five of the key you were in? If so, you would be able to do a basic lick for many songs.