When working on your pentatonic & blues scales a backing track can make all the difference. Having a tack in the background can act as your metronome, give you ideas for riffs, or even just break up the monotony of running scales. One of my favorite Youtube pages is Quist. He makes great quality tracks and is one hell of a player. Don't worry, he'll give you plenty of space to stretch out and play after his intro. Enjoy!