I want answers for my mothers bad hysterectomy operation?

about 4 years ago my mother had a hysterectomy operation which left her in a lot of pain ever since. she has had appointments one after the other she has had scannings of the body and she has even had little cameras put inside her but they still cant find the problem she is on alot of medication to keep her slightly sedated due to the pain it has taken the nhs 4 years toseek the sourse of the pain but still cant find it so i was wondering if any one out there has experienced this or knows of any one that is any info will be grat new thanks.