M.P.
Try smelling an essential oil. Perhaps swipe a bit under your nose or somewhere on your body or clothes. Also, try spraying the car with Febreze or a similar product. Be sure to wash all the clothes you were wearing in the house.
I had lung surgery and I had a lingering chemical smell for awhile. It eventually went away.
About the hiatal hernia. You have pain. If it's not a hernia, it's something else. I suggest seeing a specialist/gastroenterologist as the next step. What did your doctor recommend?
I had increasingly more serious abdominal pain and it took years of seeing an OB to finally learn it was endometriosis. At the time, endometriosis was relatively unknown. It takes time and many visits to the same doctor sometimes for a diagnosis. Once the gp has reached the end of their knowledge and skill, move on to a specialist.