Hey Eric68, I see you're relatively new here. Welcome!
As for your problems, I myself am going through a similar situation right now involving stomach problems and the lump in the throat. I was diagnosed with GERD back in November, and have been taking Omeprazole for it since and it worked wonderfully until relevantly recently when I suddenly developed anxiety along with a host of other problems. After visiting my doctor and having a blood test done to check my thyroid due to my symptoms and familial history, my thyroid test came back normal but he did say I had high blood calcium. This worried me because I had had blood drawn the year prior and had high blood calcium then as well, and the note said that I would have to go back in for a PTH (parathyroid hormone) test to make sure the high blood calcium was not a cause of the gland's dysfunction. Following reading this, I decided to look up these issues and stumbled across hyperparathyroidism, often caused by one of the parathyroid glands (small, grain-of-rice shaped glands residing behind the thyroid) becoming tumorous. Reading the symptoms, I noticed that not only had I developed many of them over the past year, but one of them was GERD; often with no prior familial history or other cause, such as age (I'm 18). On top of that, due to hyperparathyroidism causing there to be a higher amount of calcium in your blood, many people can often get kidney stones from this issue. I personally haven't had that issue but it'd probably be more likely to occur in someone of your age along with the issue.
Most people who pass kidney stones completely naturally are a little older than you, in their 50's or older, so unless you've led a life with a high calcium diet, you may want to consider hyperparathyroidism. You didn't mention that you got a blood test during any of this, so it might be a choice. If nothing else, it'll help determine whether the nodules on your thyroid are causing hyperthyroidism (which is similar to hyper*para*thyroidism but affects your thyroid gland instead and has different symptoms involving the metabolism).
Either way, to reassure you about your GERD; mine's been getting worse since the beginning of this whole issue I've been experiencing over the past couple weeks and I've experienced new symptoms similar to yours. At first, all I got was occasional heartburn and excessive gas buildup that led to nausea and sometimes vomiting. Now, if I eat anything even remotely close to what would trigger my GERD before (spicy, greasy, foods; carbonated beverages, etc.) I'll get excessive gas that leads to bloating that can sometimes move up into feeling like pressure in my chest and a lump in my throat until I expel it through belching or flatulence. I'm sometimes afraid I'm having a heart attack if I get the chest pains that GERD can cause but I keep in mind that I'm young, I got an EKG that said my heart was fine, and if I get any pains at all, they're usually on the side opposite my heart, more like near my gallbladder.
Another thing to keep in mind is the stickied list at the top of this forum labeled "This list is a lifesaver!!" It's specifically for people who suffer from HA and need reassurance of the *physical* symptoms that anxiety can cause. Sometimes I'll experience a real physical symptom that isn't dangerous and my anxious brain will run with it and have a field day and I'll start experiencing other symptoms that make me almost 100% sure I am dying but then I try and calm myself down and relax, and reading that list will often help me calm down because the feelings I experience are right on that list and I just keep rereading it until it sinks in that I'm fine and eventually those sensations subside.
Also, just a fun fact, if you do end up having a thyroid issue, most likely hyperthyroidism if you have nodules, that can often cause anxiety too!
I hope for the best for you on your adventure and make sure to check in every now and then. Like you said, people don't tend to go on the internet to tell their success stories, but it might be good to do so on this website as everybody could use an inspiring success story now and then.
Stay safe :)