Chronic Stomach Problems- Help!!!

I am 16 year old and have very frequent stomach problems. After I eat, I will experience severe upper abdominal discomfort and indigestion. Also, I get what feels like bubbles of air coming up into my esophagus, accompanied by a sort of growlng noise. The condition is worsened by excercise, and greatly lessened by laying down. I've tried eating different foods and eliminating certain foods from my diet, but it doesn't seem to matter what I eat.

Usually, I will experience symptoms after almost everything I eat, be it a meal or just a little snack, for periods of a week or two, on and off. My symptoms are usually worse the more food I eat. Sometimes it won't bother me for 8-10 days, only to come back later and give me problems every time I eat.

Symptoms will last for several (at least 1-4) hours after I eat, and are greatly worsened by excercise. Even going to the gym 2 hours after a meal, I end up feeling really indigested. I have tried taking medicine for gas and acid such as pepto bismol and tums (as well as a few suggested to me by my pharmacist). None of these work. I talked to my doctor, but he simply named several stomach disorders and vaguely said he'd run some tests (which all came back negative). At first I thought it might be GERD, but then I realized that I have no pain, only discomfort, and that my discomfort is greatly reduced by laying down, not worsened as in GERD.

What can I do? My parents have basically blown me off. They think that it can't be bothering me that much because I don't really complain about it, but I just don't complain because I know there's nothing they can do. I've ended up barely eating because doing so just makes me sick.

Please help! What could this be?

P.S.- My dad has pretty severe Dysphagia- could this be genetic?