Yes, Yoga. Yoga is a beautiful art form that is a weekly, if not daily must! The ancient practice is believe to have originated in India circa 3000 B.C. It was developed as a way to achieve harmony between the heart and soul on the path to divine enlightenment.
Yoga opens up muscles, joints, and the mind. Flexibility and strength go hand in hand because flexibility allows us to use our muscles to the max extent of their capabilities. The reason being because they are able to work through their entire range of motion with less difficulty or resistance. This helps you get into a deeper squat, for example. It also will help with the back/hip/neck/shoulder pain you're experiencing (if you're like me).
Arguably more important than the physical health benefits, are the mental health benefits. Yoga is the healthiest way to start and/or finish your day. It allows you to clear your mind and get in touch with your body, which is the original purpose of the practice. This meditative state teaches you how to breath and relax when in a tense/difficult/awkward situation. An ability to do so is a skill that is universal and a common denominator between some of the best athletes and most successful people.
Don't want to take my word for it? How about the word from one of the most bad ass humans in the world, David Goggins?
Trust me, the David Goggins post is in the works, but if you have time listen to this interview! You won't be disappointed.