I'm 34, about 168 lbs., 5'10 or 5'11, white and male, residing in the Midwest United States. I am not on any medication and haven't ever been on any long term medication. I have no diagnosed chronic illnesses, and have only had the regular sicknesses everyone has (rarely colds, flu, etc.). I get a free basic check-up each year since 2019 from work, and that shows normal blood pressure and good cholesterol levels.

Since 2019 - so roughly 4 years - I've gotten a kind of back pain, usually three to five times each year. The back pain typically starts as a light ache around 7 pm or 8 pm. It slowly grows until about 4 or 5 hours later it reaches a peak as a sharp, intense pain, the worst I've felt. It is on my back, in a band somewhere at the level of the bottom of the ribs - I'm not sure if I would say above, right at, or below the rib level. The band extends on both right and left, though on one or two occasions it felt mostly on the right. The peak pain lasts for a couple of hours or so, then recedes and eventually after another couple of hours is back to a dull ache.

Something that does help is standing in a hot shower with water on my back. While in the shower, the ache/pain diminishes significantly while I'm in there. When I get out, though, the ache/pain returns to roughly pre-shower intensity within minutes. I've tried naproxen a few times, which seemed to do nothing.

To get this out of the way, I don't think this is from physical exertion. I don't really do any physically demanding things, and the few times in these four years I have, I haven;t had the back pain. I even moved all my stuff by myself - furniture, boxes of books - into a house in my town, and didn't suffer anything like this. The only common feature I have noticed is that this pattern of pain happens on days in which I overeat. On each day I ate over 2000 calories in that day - most of those calories near noon, in one meal - I have had the pain. On all other days - in which I typically try to eat 1700 or 1800 calories total across a day - I don't have the pain. I don't really know if the eating is causative or a coincidence, but I haven't especially noticed any other common feature on those days.

I haven't seen a hospital in these years for several reasons - COVID concerns, the rarity making it sometimes seem like a random one-off thing in the first year, etc. Has anyone heard of something like this, or have any ideas about what type of thing it might be?