Watch the Shredding the Diatonic online guitar lesson by Angus Clark from Hard Rock Survival Guide: Lead
Hang in there. These concepts about scales and neck knowledge are important and will greatly impact your ability to master the instrument and go forth as the rock guitar player you want to be.
As rock guitar progressed into the use of more sophisticated techniques, guitar players looked for ways to solve the problem of picking cleanly when crossing strings. I primarily use what is called alternate picking. This creates hazards when crossing strings. By organizing the diatonic scales into fingerings that specifically use three notes on every string, as opposed to some of the fingerings we looked at earlier where there are sometimes only two notes on a string, it creates a more repetitive set of scenarios for how your hands are synchronized. And therefore it is possible to play more quickly and cleanly. This is a lot of material to get a handle on, so take it one fingering at a time and build up from a slow metronome setting. You will also want to use practice patterns to really get all of the picking scenarios and combinations down. You'll be glad you did.