Tennis balls are a great inexpensive tool that can help reduce hip pain and tightness. The pressure from the ball helps with myofascial release (eases up some of the tightness of your connective tissue).
Sit on the floor, take a tennis ball, and place it under the bottom of an imaginary back pocket. You can be on straight arms or your elbows. If you are tight here, this may be very painful. If you can tolerate it, place the foot from the same side of your body (ball under the right hip use your right leg) on your opposite thigh. Hold for several seconds (the pain should lessen, but may not disappear), then roll the ball to a new spot.
This is most effective when done regularly; the best time to do it is right before a workout, but aim for at least once a day. Chronic sitting and our sedentary lifestyle can cause or exacerbate hip pain. This simple exercise can provide relief.