This is a bit of a tricky question, because it seems to be between gastroenterology, cardiology, and inflammation.
About 5 years ago when I was 23, I began having a relatively mild pain in my center chest when I exhaled completely. At that time I was about 6'1 230LB. Today, I am 260LB and am 28, and the pain when I exhale completely is far worse. Not only that, but within this period, additional symptoms have arisen.
When I eat, often times when I stand up I'll get this weird spasm in my diaphragm that seems to go with my heartbeat. It's almost like my heart is pressing against something which causes the heartbeat to be felt. This only lasts for maybe 10 beats (15 seconds or so).
I do often get reflux, but I don't really get burning usually. More often I'll get wet burps or feel almost an irritation above my stomach. Tums will usually relieve this.
The most disconcerting of my symptoms are the chest pain. It is not a burning pain, it almost feels like somebody is trying to pry my chest open as I exhale. It is located along my breast bone right down the center, and doesn't really extend to the left or right much. In addition, the pain gets irritated by eating larger meals or spicy/high fat foods. If I irritate it too much with that, I will start to get PVCs (About one every 10 seconds). Unlike the spasm when I stand up, which are normal albeit hard heartbeats, these are a weird sensation beat, followed by a longer than usual pause, then a really hard beat. When the pain is more intense, my heart rate tends to be elevated as well. Any sort of heat or pressure on my chest causes significant discomfort.
Advil does not seem to do anything to the pain - it almost seems mechanical, and is exacerbated by touching it or exhaling. It is 100% reproducible, and is better in certain positions. In addition, PPIs, Zantac, and Tums seem to help the pain a little bit they never get rid of it completely. I've tried oral steroids, but they gave me an irregular heartbeat after the first dose so I stopped.
The only thing that seems to lessen (but not eliminate) the pain is time, not eating, or only eating small amounts with non-aggravating food choices.
Doctors in the past told me it may be costochondritis... but it's been 5 years and is getting worse, and appears to be involved in a complex of systems that is not related to costochondritis (Such as interaction with heart and gut). I've had an endoscopy, echocardiogram, stress test, all came back normal. The Gastroenterologist said he did not see a hiatal hernia.
So with Chest wall pain, gastro symptoms, and heart racing/palpitations all in one... Im guessing it has to be fat or something else pressing on things in there, maybe compressing the vagus nerve (Which may explain the palpitations and racing heart), irritating the nerves around the chest/esophagus (Causing the chest wall pain).
Has anyone had or heard of symptoms like this before? They're really starting to impact my life. Currently I am making an effort to lose weight in hopes that it will lessen the symptoms, but so far they're about the same or a little worse after ~15 pounds of weight loss (275 to 260). I plan to schedule another appointment with my gastro soon.