Ken2828,
Here's what I've read:
You're a 30 year old male with a wife and children (as well as one on the way), changing careers, foreseeing the future, juggling a great deal of changes, facing new challenges and adding new responsibilities on top of everything else...daily life runs fast huh?
Your symptoms:
Bouts of racing heartbeats that seem to come in short runs occurring within a cluster of a few days, the pacing of your heart rate seems to run fast then slow to normal, they can come at anytime regardless of what you are doing, sometimes after sitting (resting) then standing-up can bring-on an episode, exercise seems to speed the heart but then you feel fine, your diet has lent itself to soda's and fast foods but you are making changes, often -you are without chest pains but feel some tightness, the tightness seems to relate more to acid reflux but the cardiac bouts confuse this issue, you've taken several meds to relieve acid reflux and what do they cause, lying down seems to bring symptoms that go between the reflux and bouts, you get trapped gas and burps, feel like you need air, when you are consumed in another activity the bouts tend to go away, cardiac maneuvers seem to relieve the bouts, and all the new changes and responsibilities in your life adds a bit of stress-load to everything.
What I'm giving is merely an opinion...some infections such as respiratory, bronchial, sinus, or even dental can cause the following symptoms; fast and slow, weak and strong rates that come and go (palpitations), mild changes-both up and down bodily temperatures, tightness in the chest, sometimes a tenderness in the chest, feel like you can't get enough air, dry cough, weakness that can initiate cardiac reactions when exerted, retention of fluids (edema), and all of these symptoms need not happen entirely. Similarly, all of those symptoms can solely come about and/or be exacerbated with fear (even if it's mild), stress, or some other unrelated medical cause. Those symptoms can also occur due to hormonal changes, bodily stages as we age, our diet, or mild issues with glucose (such as hypo or hyperglycemia..etc). Glucose, the sugar and insulin factor in our blood, can relate to many of your symptoms and a fast-food, soda intake can contribute to this. Blood pressure is also another factor. It can be the primary cause or an element combined or causing glucose issues, or solely related to stress (effecting oxygen intake) and/or diet. All in all, a lot of things other than cardiac can be the core cause. In terms of cardiac, in some cases as the heart acts-up a person can become acidotic (related to gastrointestinal issues-such as burps), hypovolemic (diminished blood volume, diminished water content-thirst), dig-toxic (withhold digitalis, or too much mineral intake), and hypoxic (deficiency of oxygen, poor blood gas-needing air). The burping and need for air tends to come with actual cardiac bouts, so this is a normal reaction. Added to that, further stress and fear due to the bout can heighten the symptoms. Without distractions, you are keenly aware of the symptoms but they will go away when you are occupied lending it more towards fear, as in an adrenaline shift. You say that you are getting rapid heartbeats at 120 bpm (beats per minute) but this has occurred within and up to 45 seconds and not an entire minute? Yet, Vagotonic or Vagal maneuvers, to push your abdominal muscles down or out as to strain hard-like you were passing difficult bowel matter, a hard cough or cold water relieves the run and often that tends to work if it's a cardiac episode. If acid reflux is the core, drugs for that issues may contain magnesium or calcium. The conductive electricity of the heart trades sodium and potassium to initiate the flow of its electrical current (known as the sodium pump or enzymatic pump). All together, however, there is a balance of potassium, sodium, calcium, and magnesium in the heart and they all work off of each other in a plus and minus factor. When you take doses of magnesium or calcium you can, even if it's mildly, alter that chemistry. They shift and adjust effecting everything from the electrical conductivity, ATP (adenosine triphosphate-energy for muscle contractions), adrenaline, cholesterol, glucose, and lot of other things. Mineral balance is critical, as with magnesium and calcium that are two different elements that have actions that oppose each other but function as a team. All this technical talk means that the acid reflux pills could be altering you mineral balance and you are having a cardiac response. Then there's plain old stress, the big one...Enie is so on it, it can kill, truly compound, create, and throw havoc into the equation. All the things I've mentioned are not intended to confuse you, but to point something out...these boards are very helpful, but there is no substitute for a good health screening. Go get a physical, especially if it's been over a couple of years, with a really good blood panel. Let your physician know that you want an overall health check for two reasons, because you want it due to bodily changes and you have some concerns that have blurred lines between gastric, cardiac, sugar, or whatnot compounded by everyday stress. Let the doctor know everything that is going on. Bring in a written list, like the one I summarized, and read it off to the doc...don't feel funny-do it. And just in case, if the physical is conducted by a nurse request a separate appointment with a physician and hold your ground. In any case, try to get yourself checked-out as soon as you can. No one on this board should diagnose your problem, including me, but we can help and that is what this is about. Listen...stress adds to stress, adds to stress and so on...stop pondering and adding to the load of your daily life and get it checked-out. You have a beautiful family who wants you to be around for a very long time. Early symptoms should never be ignore until they become chaos. No martyring...step-up and check-it out. And finally, if needed, go to an ER. Sure, it's a hassle, lots of drama, wait, and frustration but some conditions are periodic, and only episodic, and must be diagnosed while it is happening...so going to the ER might well be worth it. Get better and Good luck to you Ken2828.