HI...if u have GERD or other stomach issues u can sometimes have these types of pains...IBS can also cause it.....look at ur digestive health and see if that could be a contributor to this pain.
Get diagnostic imaging. I have the same problem, but I was on high levels of painkillers and didn't really notice more than the "dull, achey" feeling you described until I got off the pain meds. Now, it becomes excruciating as the muscles tighten up. I am going for x-ray and MRI on Monday. Sounds like we may have the same type of injury. I'll try to post results as soon as I get them on my profile page.