Let’s meet the piriformis muscle.
Located deeper than your glutes, the piriformis helps stabilize and rotate your hips. The very large sciatic nerve lays next to the piriformis. Fun fact: In 10%-15% of people, it can run through the center of the piriformis muscle.
If that muscle is tight from excessive sitting and slouching, it can push on the sciatic nerve causing pain down the leg. Massaging and stretching can help. Here is just one way to self-massage the piriformis.