We work hard but can we rest hard? Sour muscles comes with progression and taking care of the issue is crucial. Muscles are big and need to be treated with a strong hand to activate the blood flow to recover and eventually heal. Since we do have a self preservation it means that we might need a helping hand from time to time or we bring out the grid.
The best one I found so far is The Grid from TriggerPoint Performance Theraphy. If you wanna try out the feeling on a budget, gaffe-tape two tennis balls together(called a peanut) and apply them with pressure on the sour muscle.
The concept is to find the sour spot and apply pressure to it. Usually its in-between two muscles. Someone who is fantastic to explain and educate about self healing in muscles, joints and mobility in general is Kelly Starrett at MobilityWOD Make sure to check out one of his tutorials, they are amazing!