who should my 29 year old daughter see for severe lower backpain?

Her symptoms include...very frequent headaches, dizziness, nauseous or gassy stomach, and chronic fatique.  She is overweight, but she sounds like me (her mother) already.  Family history of fybermyalgia, diabetese, cancer, gerd, irritable bowel syndrome.  I am becoming more and more concerned about her as these symptoms just keep coming on more and more frequently.  She has never been one to complain.  She is pretty matter of fact and takes pain pretty well.  Her family physician just told her to do some stretch exercise and does not seem to take her too seriously.  She did get siatica while having her only child by intense hours (and hours) of pushing.  But this pain is low but higher than the sciatica.  Motrin helps very little and she is beginning to take a lot of them!  Not like her at all.  Who should she see?  What tests should be taken.  She does have hypothyroidism and PCOS along with many cysts and endometriosis.  She has been advised to have a hysterectomy soon.  Please help.  Thanks, Deana