Right, so you want to learn how to stretch your fingers on the guitar. There a few great exercises that I teach that help my students stretch there fingers. When you first start playing it's really hard to make that chord sound good, or that scale sing, but I got something to share... By practicing these three tips and techniques you can play any chord and scale with ease.
Play the finger stretching exercise. You start by putting your index finger on fret one of string 6 (the biggest string). Then you add your middle finger to fret 2 , your ring finger to fret 3, and your pinky to fret 4. This is all on the same string. By keeping your last finger on the fret board and adding another, it really stretches your fingers out. Repeat this same process on strings 5-1. When you descend this scale you will be peeling off your fingers after you play the note. Do this 4-10 minutes a day.
Practice switching between chords in your left hand only. For example switch between a G chord and a C chord back and forth. You want to make sure that your thumb is not popping out from the neck of the guitar like a gofer. Your thumb should be going with the neck of the guitar (horizontal). When you play these chords you want have your fingers arched and you also want to be playing with the pads of your fingers. Practice switching between chords until you feel comfortable enough to add rhythm with your right hand.
Practice your favorite scales. Scales are great because we don't have do think about the rhythm that much. We get to focus almost entirely on what the left hand is doing. When you play your major scales end each one with a half or whole note. You want to give your brain the chance to recover and calculate how to make your next scale better and how to make your fingers stretch more. Practice your major scale for at least five minutes and then move on to your other scales. Scales will really stretch your fingers if you put the effort into playing them. Imagining your fingers stretching before playing a scale never hurts either.