Igualmente

Yes, that can be an issue. I wonder if you have exhausted all avenues. I have in the past, under care of a physiotherapist for an injury, been told to keep taking anti-inflammatories while doing physio. I've also done myofascial/trigger-point releases prior to stretching. Also, there are several variations on piriformis stretches. I wonder if you can see a doctor and a physiotherapist for that. Of course, you may have already gone down those roads.

Also, one theory on the cause of piriformis syndrome is that other hip area muscles are not activating properly. Perhaps working on your gluteus medius would help, assuming you don't aggravate the sciatica. Again, a physiotherapist could advise there. There is also information about movements like the side-lying clam that can help activate the gluteus medius.

Lastly, if hamstrings are an issue, you should be able to do something there without aggravating sciatica. Aside from gentle stretching (there is controversy over the value or harm of aggressive stretching), if you are in a seated position all day long at work with your hamstrings contracted, you may want to look at how you can have your hamstrings in a different and longer position without really doing stretching.