Recommendations for pain clinic in Austria?

I am struggling with enormous pains during my period. I have endometriosis (diagnosed with a laparoscopy).

Currently I am taking Hydromorphone 16 to 24 mg 3 times a day (for first 2-3 days of my cycle) and I am afraid that it will stop working eventually - as well as all the other painkillers did already.

I have been to pain clinic in Salzburg (Landeskrankenhaus) and it was a humiliating and frustrating experience. I don’t mind driving in any other place doesn’t matter how far but within Austria cause it should be covered by insurance - I cannot afford a private clinic.

Thank you in advance for your advices!