Sorry to hear this. Two things I suppose... Firstly, what painkillers are you taking? It might be that there is something stronger or a different combination that works better for you. Secondly, do you have confidence in the consultant who operated on you. Did they specialize in endo? How severe was the endo they found. Severe - in the sense of was in deep and infiltrating? Obviously, even a few patches of superficial endo can cause a lot of pain - but they might be easier to treat than infiltrating disease. For deep and aggressive endo you may need someone with more skill.
I understand how difficult and frustrating it is. I have daily pain despite heavy pain meds, various surgeries, past hormonal treatments etc, etc. Some people find a change of diet can help a little or a lot. Although a complete endo type diet did not help me massively, there are certainly some foods that flare the endo that affects my bowel and bladder (wheat, citrus, chocolate, certain vegetables). Some people cut red meat out. I can't comment on whether this would have made any difference to me as I've been a vegetarian for over 30yrs anyway.
Consider trying to find an endo specialist if you have not already - and get a 2nd opinion. If you put a post up asking for people to send you pm recommendations for your part of the county, you might get a response. We are not supposed to name consultants here (though, it baffles me why sometimes) but people might send you a pm.