You do not mention your age. I bring this up as routine aging does come with its own aches and pains.
You report that your pain is a 1 on a 1-10 scale. I do not quite understand why a pain of 1 would be troubling you (1 = low and 10 = high).
You mention that you lifted weights several years ago. What about now? Are you fairly sedentary? I bring this up as you mention that you see a chiropractor who has commented on your posture. If you have a rounded posture (forward head and rounded/slouched shoulders) you will experience discomfort when the body is fully opened and stretched outward.
The suggestion raised of chrondoitis is a valid consideration. You need not have each of the identifying symptoms. The interface of the sternum and individual ribs is a site of continual micro movement with each breath intake and exhalation. Inflammation due to repeated micro movement is the basis of chrondoitis.
You may want to find a "functional medicine" physician. These MDs focus on how the body moves and functions in assessing for pain and dysfunction. As you have had fairly extensive imaging scans and a GI work-up without a distinct diagnosis, a functional medicine MD might be a insightful nexr step.
- K -
Post Edited ((Seashell)) : 6/4/2017 4:20:00 PM (GMT-6)