Your hips have an important job! They help mobilize and stabilize the lower extremities. Side-Lying Clam Exercises are a great way to engage your hip external rotators.
Technique matters. Too often, people push themselves into harder exercises without having a solid understanding of the techniques needed for that particular movement.
When sitting, your hip position in your chair can make a big difference on your lower back. This is especially true for folks with disc bulges or herniations...