I have been on Gabapentin for sciatic/nerve issues and it's changed my quality of life. Had a spinal fusion @ Mayo Clinic back in 1982 and as of the past 5-6 years have had an issue with numbness, nerve pain down my right leg and into my foot (L4-L5) impingement. It no longer flairs up, since the Gabapentin Rx. I'm on 300mg/3 x/day and it's been a game changer. Best of luck to you. Mayo Clinic figured it out, was @ Cleveland Clinic and UPMC prior, but Mayo Clinic was worth the trip for sure.
I had sciatica pain. The best recommendation I had was to stretch. Lots of stretching. This helped release the pinched nerve causing it. Alternating ice and heating pad can also help. The person that I found best to help with sciatica was a physical therapist. I've had that pulsating therapy you describe at a chiropractor too. It definitely is weird, isn't it? I am not sure it ever helped. My chiro also did ice therapy. When he told me about it, I was like no way. But it did seem to have a positive effect. It pretty much is exactly as it sounds, icing the area thoroughly.
I see you have tried some stretching. But I'd keep at it. And if it is still hurting, see a doctor.
Have you consulted with a board certified spine surgeon or had an MRI to find out the cause of the sciatica?
Seeing a spine surgeon most iftenbdoes not result in needing surgery, but they can give you far better treatment/diagnosis of the actual causes of the oain.
Chiropractors are great but diagnosing the issue isn't typically their specialty, and diagnosing anything other than alignment issues from xray can't be done.
Xray don't show disc herniation or bulges, nor compressed nerves that may be causing the problem.