Yes, chest pain that worsens when bending over and in addition to other gastrointestional symptoms (burping) is usually indicative of heart burn, also known as acid reflux or gastroesophageal reflux disease (GERD).
In cases of GERD, acid from the stomach moves up into the esophagus (throat), and can cause a number of unpleasant sensations including anything from heartburn or chest pain to regurgitation, hoarseness, difficulty swallowing, feeling like something's stuck in your throat, coughing, belching, or burning in the throat or mouth.
The exact cause isn't known, and some people just seem presdisposed to having it, but other risk factors include drinking alcohol, pregnancy, obsesity, smoking and eating certain foods.
Eating small frequent meals, and avoiding any known food allergens can help. You should also avoid overeating, as this puts pressure on the esophagus and stomach and makes the condition worse. Also elevate the head of your bed 6-8 inches to decrease excessive pressure on the diaphragm, and avoid eating before to going to bed.
There are also remedies available over-the-counter such as prilosec or zantac for long-term relief, and antacids for more immediate relief. Some people, however, require more aggressive treatments and prescription medications, such as proton pump inhibitors, to relieve the problem.
Ideally, chest pain should be evaluated by a doctor at least once to rule out any more worrisome problems, such as cardiovasuclar-related disorders (heart problems, high blood pressure, angina, etc), or problems of a different nature that could not otherwise be treated, such as gastritis or esophagitis (infection or inflammation along the gastrointestional tract). If your pain is severe or recurrent, and does not respond to any of the over-the-counter remedies (pepcid, mylanta), further diagnostic investigations are recommended.
I hope this helps, and hope you have a good night!
Pain from GERD can certainly become progressively worse if left untreated. Without adequate treatment, complications can start to arrise: esophagitis (chronic inflammation, ulcers, bleeding), and even change the nature of the lining of the esophageal tract (called Barrett's Disease) which is also a risk factor for cancer of the esophagus, scarring of the esophagus, which tightens it, or causes stricture.
Ideally, you probably need further diagnostic procedures to confirm that it is reflux causing the pain, and the extent of the damage done. This is usually done with endoscopies, barium studies, and probe tests.
GERD doesn't always have to occur as a result of something you ate. The cause may be something more general such as:
Antacids and foaming agents can help relieve symptomatic GERD, but won't prevent or cure it. Hydrogen gas blockers are available OTC and by prescription (Tagament, pecid, axid, zantac) and also provide short-term relief, but are not meant to be used for more than a few weeks at a time. Proton pump inhibitors are used in a majority of the cases, and are probably one of the most effective medications for GERD. These include: omeprazole (Prilosec), lansoprazole (Prevacid), pantoprazole (Protonix), rabeprazole (Aciphex), and esomeprazole (Nexium).
Another group of meds, called prokinetics, help GERD by improving the function of the sphincter and quicken stomach emptying. As I mentioned above, a ring of muscles (sphincter) that separates the stomach and esophagus can be weak in some people, but prokinetics might aid in tightening it. Bethanechol (Urecholine) and metoclopramide (Reglan) are used for this.
The best treatment for you will depend on the nature of what's causing your particular condition, so again, further diagnostic tests are advised.
Sometimes, a doctor will diagnose GERD based on symptoms and history alone, but pH probe tests can also be used to diagnose this, as well as endoscopic evaluations, imaging studies, and esophageal manometry (to test for weakness in the sphincter between the stomach and esophagus. Since you also have a history of conduction problems with the heart, blood test and CBC, chest imaging studies (xray, CT, MRI), EKG (electrocardiogram), and exercise stress test might be appropriate as well to rule out cardiac problems as contributing to your chest pain. That esophagitis has already been seen is a very good indication that you do have GERD, however. Technically, any type of "itis" (esophagitis, gastritis) means that the tissue is simply inflammed. The trick is to determine the cause for this inflammation. Esophagitis can be inflammation of the esophagus from repeated exposure to stomach acid, or even from bacterial or fungal infections, or both.
It's true that there are a lot of bacteria in the intestinal tract, and they serve very useful purposes. At normal levels, they won't cause a problem, but when a person's immune system is weakened for some reason or another (stress, illness, damage to the tissue of the GI tract), these bacteria are capable of multiplying too quickly and can cause an infection by invading the tissue in that area. If the tissue is already inflammed or damaged from something like excessive acid exposure, it's much easier for the bacteria to invade the tissue and cause an infection. If left untreated, these infections can spread to nearby tissues or blood stream, and set off the whole body, as you mentioned.
And yes, intestinal health does help the immune system. The entire immune system isn't based on the intestines alone, but research suggests that normal levels of certain "friendly" bacteria in the intestines help strengthen the immune system. Bacteria such as Lactobacillus acidophilus and Bifidobacterium bifidum,which are normally found in the intestines, assist the body by defending it against toxins, bacteria and allergens. Some people take supplements called "probiotics" for this reason, and certain types of probiotics are used to even treat GERD, but the effectiveness hasn't been evaluated by the FDA at this time. You can read more about them here: http://en.wikipedia.org/wiki/Probiotic
Were you treated for the H. pylori found from your endo procedure? This is a type of bacteria that is not a part of the normal flora of bacteria in the stomach, and can lead to gastritis, esophagitis, and acid reflux. In fact, this might be the cause of your symptoms. H. pylori loves the stomach environment, and isn't likely to go away on its own without treatment. Minor infections can be treated with bismuth solutions, such as Pepto-bismol that you find over-the-counter, which kills the bacteria. If the infection is more severe, however, oral antibiotics will be required to kill them efficiently.
I hope this helps!