Hi you really have been poked and prodded haven't you? I feel really sorry for you, but I do have one idea that might be worth you finding out more about.
Reflux is sometimes a secondary illness to other conditions. Some conditions can also make you very sensitive to drugs, so more likely to show a reaction.
Your symptom of being weighted down on the chest is a classic symptom of reflux, some say its like having a car sitting on your chest. (I run a support group for reflux)
Fibromyalgia and hypermobility sufferers have a lot of pain and aches, the latter due to collagen problems. Ehlers - Danlos syndrome is another condition where reflux is secondary.
With Fibromyalgia it also makes you sensitve to medication... my sister has it and is so exhausted all the time as she doesn't get enough grade 4 sleep. She lives in pain most of the time. There are many support groups about that could give you info on this and actually will show you where they suffer the pain.
I am not medically trained, I am just throwing a few more possible avenues to check out. Good luck