Can't get an answer from the docs

Ok I know it won't do me much good to try to seek medical help from strangers on the internet. But I sure can't get it from the damn doctors who keep telling me I'm fine and can't figure out what's causing my symptoms. I'm not sure they even believe I have symptoms. I'm just desperately hoping maybe someone here has had experience with this and maybe has a little insight.

So the issue. Ever since I had my baby back in July, I've had this regular issue where I'll have incredibly intense pain in my upper back, like shoulder blade area down to maybe mid-back. This is often accompanied by chest pain and nausea. I can't seem to figure out what causes it specifically, but typical pain relievers do nothing. It seems to be most common late in the day and middle of the night and will last anywhere from 30 minutes to a couple hours. When my baby was new, it would happen every two weeks, almost like clockwork. By the time he was a couple months old, it slowed to about every 3-4 months. It may not be frequent anymore, but it sure as hell is uncomfortable and I wish I knew what caused it so I could get it to stop all together. It's currently 4am and my baby who rarely sleeps is actually sleeping and I can't freaking take advantage of it because I'm just getting past another episode (pain is decreasing but still there and I'm still nauseous.) Has anyone ever experienced this? Any ideas as to what direction I can point the doctors in? Literally the best they've ever come up with is "heartburn". This ain't no heartburn you idiots. I know heartburn, I had it while I was pregnant. This is NOT it. I really appreciate any ideas!