You might want to find a remedial massage therapist and get them to loosen off the piriformis muscle (one of the hip rotators) as it is quite often guilty for sciatic pain due to the sciatic nerve going through the muscle - so if the muscle spasms through overwork/understretching the inflamed area touches the nerve when it shouldn't.. They'd also probably give you a good back massage while you were there, and work out any other kinks created by poor posture during repetitive work tasks.
If you want to test the piriformis, you can get a hard ball, your thumb or a doorknob even, and push your glut (bum) muscles against it until you find the deep muscles. If you find a very tender point, sit into it, literally as much as you can bear, you'll relieve the trigger point by forcing the belly of the muscle to relax through the pressure. It's pretty much what the RMT would do but under your own control so you have to go there..
In our pilates classes we do this regularly to maintain the hip rotators and it really does work - we use trigger point massage balls or lacrosse balls - a tennis ball is too soft but some dog play balls are rock hard and big enough. A golf ball is too small and the pressure thus too intense - I've tried it! You can see some funny faces when a class of people are doing the trigger point work, but it really does help! I've given the info to several of my massage clients and it gives them some relief or complete management system depending on symptom/cause in each case.
Stretch wise, hug one leg to your belly with both hands and stretch the other leg right out a couple of inches above the floor (lying down), breathing out as you hug the knee in and out as you stretch/swap legs. Repeat 10x very slowly each side even if the other side appears not to have any tension, you'll be surprised.. There are other stretches but I'm not the best at describing them, check on google for piriformis stretch, sacro-iliac stretch and sciatica stretch, then find what works for you and keep doing it daily or 2x daily then regularly at least a couple times a week even after it's pain free for maintenance.