Your buttock muscles (also called gluteal muscles) are large, powerful muscles. When they become ‘too tight’ they can cause pressure on the sciatic nerve as it passes through your hip area.
The sciatic nerve is as large as your finger and is usually found behind some of the large gluteal muscles.
Nerves hate to be pressed on and so the sciatic nerve will complain by causing symptoms of pain or nervy sensations in your hip, leg or even in your foot!
Here’s the link to an article with directions on how to help those gluteal muscles relax. If they are the cause of your sciatica it will make a big difference.
http://www.simplebackpainrelief.com/sciatica/how-to-massage-gluteal-muscles-for-back-pain-relief/