Hi D.,
I have a few suggestions for you as both of my boys have had similar issues. With my first son, the issues started when he was about 6 months old, and he was MISERABLE and screaming when he was laid down for more than 45 minutes, at ANY time of day or night. Which means I was waking every hour for overnight and struggling to get naps in appropriately for him AND me. When we would pick him up he would always burp and spit up, often projectile. They said he would outgrow it, until when he was 13 months old I finally said this was insane and I thought that we needed to try to help him, and my sanity b/c I was NOT sleeping from him waking so much. His regular pediatrician prescribed ZANTAC for him, for reflux. I wasn't comfortable giving it to him, so I decided to call a naturopathic pediatrician. She was AWESOME!! She had me describe to her what I ate - EVERYTHING, and what he ate, and then immediately told me to eliminate this list of foods for a time and see if there was any improvement. Oh my goodness there was MAJOR improvement!! Within 2 weeks of eliminating all of those foods (sure, it was tough, but SO worth it!) he was sleeping through the night, no more burping and projectile spitting episodes. Turns out the foods that we were eating a lot of (wheat, dairy, banana, potato, corn, refined sugar) are mucous forming foods, and it would increase the amount of mucous in his stomach, which would aggravate it and cause all of the problems. He's 2 now and can eat whatever he wants without issue. It was, for him, just a matter of waiting until his system matured a little bit more - it was more sensitive.
Then, with my 2nd son, at 3 months he started being puker in a MAJOR way (not your typical baby spit-up, but I would be SOAKED from puke after every feeding). When I asked my naturopathic pediatrician about it, she started with two suggestions for now (he's currently just 4 months this week). First, she told me to make sure that he was tummy to my tummy when nursing. She said sometimes after we get into a routine of nursing we don't always notice that their tummy is more facing up, instead of against ours, and that can cause a latching problem, which will in turn affect the air that they take in which can affect their digestion. So I pay attention to that more now, and also she recommended a wellness chiropracter. I was a little taken aback by that, since he's so little. She said that sometimes when they come through the birth canal their back can get out of whack, which will affect everything - digestion and all. I checked it out and it has made a HUGE improvement for him too. I brought him to this guy who goes to hospitals to do baby adjustments (who knew?!?!?!) and he holds Ben (my son) gently and makes light adjustments on his back (not like he would do for an adult). Ben smiles at me through the whole thing, and there is ALWAYS an improvement in his digestion after we go. Maybe you could find something like that where you are?
I don't know about the Barium tests, and I certainly am not going to say those doctors don't know what they are talking about. However, if you want a 2nd opinion, I highly recommend the naturopathic route, if you can find one in your area that deals with children. I would make sure its naturo, not homeo. I took my first son to a homoepathic doctor before the naturo, and all he did was give him a thousand pellets to take and it didn't make a difference, let alone make sense to me. The naturo took the approach that what we put in affects how we function, so lets investigate those options before we do anything invasive or harsh medicinally. It worked for us!! I was so pleased that I still take my kids to my regular pediatrician for their wellness visits,etc., but if they are sick, I call my naturopath. From seeing her, my kids are really so healthy and get over their little colds and such (if they even get them!) so much faster than their peers.
Good luck!! I'd love to hear how it works out for you, since I know exactly what you're going through!