My 6 year old Leonberger groans only when lying down, not when getting up?

[LeoGirls]

I am worried about my dog as posted yesterday.  I have had blood tests done and x-Rays and she is eating well.  Pain relief hasn't stopped the moaning.  I was very sad to read what happened to your beloved dog and now am really wondering what to do.  She is 6 years old and 62 kilos which is a healthy weight for her giant breed.  I do fear that there is something serious lurking behind the groaning and maybe the best thing is to get advice from other Vets until we find the cause?
It is really helpful reading other comments and I genuinely feel sad for those who have lost their best four legged friend and want to do what I can to help mine so I can assist her whatever the cause is.  There seems to be a division in comments between those who say groaning is normal and those who have been through dreadful experiences ending in death of their loved companion so I am finding it hard to know how to react. Any thoughts?
Thank you