The awesome thing about guitars is that a person can pick one up and in a short time, start rocking like his favorite rock star. The drawback to guitar playing is that a lot of bad publicity has been attached to”learning”. As if knowing something about music will stunt your growth. I have always loved how people say that Eddie Van Halen never took guitar lessons. True, but he took piano lessons for years and his father was a talented jazz clarinet player. The point is that he was indoctrinated, steeped, and highly educated in music theory and technique before he ever picked up a guitar. He knew all of the musical rules before he ever went breaking them.
The first thing to do is learn a scale. Then learn how a scale is built. What is the combination of whole steps and half steps that make up a major scale? What are the chords that can be built on each degree of the major scale? Since you are a guitar player chances are that you will bump into the pentatonic or blues scales. Learn some licks from Albert King and see how notes of the scale belong to the chords that are being played. Rules are being followed and broken, and it helps to understand what’s going on. Albert King may not have been educated but trust me, he was schooled.