Hernia with GERD?

Hi, I'm a 23 year old male. A few months back I was lifting something heavy and felt pain on my left side of my abdomen. This feeling lasted for about 3 days and calmed down. Since then I could feel light pressure when i would work. I work in a warehouse so I do a lot of lifting. I also take Kung Fu classes. recently, about a week or so ago, we kicked our Kung Fu class up a notch and I felt that pain in my side again. Since then I have been feeling a pressure or tightness (it's hard to explain.) on that side. I went to the doctor because it was not going away. He asked me some questions, had me do some sit ups, which caused me to feel the tightness and pressure a lot more. He told me it was a pulled muscle and that I need to take it easy. Went home all relaxed. That night though I had a sudden feeling of dizziness after dinner, followed by heartburn and some light nausea. I thought I was catching something. The next morning was the same. Later that second day it faded. I had it happen again and its happening right now, tonight. I feel that tightness in my side more while sitting, and I feel I have to burp a lot more than normal. Something feels off with my digestive system. I started looking online about these symptoms and something that came up under tightness on side was a hiatal hernia. It said some of the symptoms is GERD which is like a chronic heartburn. The thing that throws me off though is the dizzy spells that come with it. My head feels like a balloon and I feel I need to rest it somewhere. Then the waves of burping and nausea (dizzy feeling doesn't help nausea.). No vomiting, bowel movements are normal. I will say though, each time I had this happen was after drinking caffeine earlier in the day. I had some strong coffee earlier. I have a bit of a caffeine addiction. Also had alcohol last night. I figure dehydration could be it too, but part of me wonders if its connected to the tightness in my side. Wondering if my doctor was wrong and I really have a hiatal hernia. Any of you know anything about this or have an idea of what it could be. I'd hate to go back to the doctor only a few days later and spend another $30 for nothing, or if it is just dehydration. Any help here would be appreciated.