I've had pain under the left rib cage for 3 yrs now. ULQ pain. I have reflux indigestion. Endo/colon, CT Scan MRI ultrasounds. Only have sm HH. Advise

How small is HH? symptoms may still be related to the hiatal hernia and gastroesophageal reflux. If you are not being treated for acid reflux then there are ample OTC treatment such as Prilosec and the like. Zantac (ranitidine) and Pepcid also excellent. I also presume the spleen is normal in size. If spleen is large it may be tender. On a rare occasion a kidney stone may cause symptoms but presume there aren't any . Good luck.
LUQ pain?? If your pain is originating from a hiatal hernia then there is a surgical fix for it wherein they stop your stomach from sliding thru the diaphragm into your chest cavity. There are other considerations too but if this has been going on for 3 years I would be searching for a better solution than whatever you have been doing unless you admire the Marquis de Sade.