Advice please

I have been suffering with a pain in my right side between my hip and ribs that starts as a nipping sensation that’s gets worse and worse till it become a swollen throbbing feeling that spreads to my groin. (Almost like there’s trapped wind)It appears to “flare up” and isn’t constant. Iv had a ct scan of kidneys, gall bladder ultrasound, overies where seen last year through many scans I had whilst pregnant. Iv had stool sample tests done-all fine, and most recently a cystoscopy of the bladder-all clear. So the dr is pursuing endometriosis as a possibility. The thing is Iv never had heavy or excruciating periods. I do get strong back pain for a day or too but other than that they are bearable and regular. I have however suffered from “uti” type symptoms and pain when pooing whilst on period for as long as I can remember. Iv lost count of the amount of times Iv been to the drs with UTI symptoms and the dip test be negative. I just wondered if this sounded anything like any of your experiences. I don’t want to get my hopes up that I’m nearing an answer if these symptoms don’t fit.
Thanks for reading x