I have been trying to have a baby for 10 years, please advise?

I have been experiencing diarrhea on and off for a very long time. With an ongoing pain in my lower left stomach. Probably close to the descending colon, inguinal ligament or the rectus abdominis. Scans have not shown anything out of the ordinary and doctors usually just talk about a hernia.

I am 46, I have one child (18y boy with my ex), but I have been trying to have a baby for 10 years with my now wife. We have done all IVF methods, even with donor eggs. But, the embryo does never survive the 4th or 5th day after the embryo transfer.

I like suggestions on what diagnostics and tests I should do. Are there any specific blood test or others that I could order, to further analyze my situation?

Medications: None