Have you ever sat on the toilet and struggled to wipe your ass? Do you struggle with reaching your seatbelt in the car? Do you fail at the overhead squat? If you answer "yes" to any of these, then you lack shoulder mobility.
The shoulder is an incredibly mobile and complex joint that needs to work with your scapula and thoracic spine (upper back). For the shoulder to function properly you must have an adequate amount of thoracic mobility. To address your mobility restrictions, begin or end every workout doing some soft tissue work. It'll help loosen restrictive connective tissue and increase blood flow to the areas targeted.
Place the foam roller at approximately a 45 degree angle across the body. Place your palm flat on the floor with the outside of your pec over the roller. Roll back and forth concentrating on the areas that are the most sensitive.
Place the foam roller just above your elbow with your arm extended. Place your head on your bicep for extra pressure as you roll up towards your shoulder. Pause over the areas that are most sensitive.
Place your palm flat on the floor with the side of your body over the foam roller.
Rock up, down, and back and forth, working your way from the shoulder to the mid portion of your side. Take your time on the areas that are most sensitive.
Place your shoulder blades across the roller with your arms behind your head or across your body. Roll from the top of your neck down to your mid back while lifting your chest towards the ceiling. Again, pause over the areas that are most sensitive.