A problem with your Sacroiliac (SI) joint makes you feel like your hips are out of whack. Sometimes it will cause pain in your back and radiating pain down your leg as well. Leaning sideways and sitting on just one cheek will only make things worse. But stretching and posture improvement efforts will help your pain and straighten you out again!
Being sure that you are symmetrical will make your hips feel better. That means standing with equal pressure on both legs with both knees straight. Sitting on both cheeks without crossing your legs or leaning on the same sided arm rest all the time. Swinging both legs out of the car and Then standing up, rather than putting all the weight on one leg while you dip and dive under the car edge. Stretching both sides of your body, even if just one side feels tight. And doing unilateral strengthening so that each side is held accountable. Those are the things that will keep your SI in place. There are some specific core and hip strengthening and stretching exercises that I have put together that will do the trick. Check it out! You’ll feel better today, and it will take away the chronic nature of your pain, too.