My lower back is very painful &stiff if i sit or stand too long. is there anything i could take or do to make it better?or exercises /stretches?

Exercise and Stretch: Lower back pain has numerous etiologies, at 21, unless you had an injury, stretching and exercise should be beneficial. Strong abdominals will support and stabilize the lower back. Stretching the lower back, hamstrings, and buttocks muscles will help tremendously. Exercises and stretches should be done and learned by a therapist, trainer, or a person who has experience with these.