I Have Been Having Black Outs For About Two Years

I have been having black outs for about two years but in the last two weeks they have gotten worse. I went to my family care doctor who wanted to start with echo and a two week heart monitor. The echo was normal and so far the only thing happening on monitor is tachycardia. I am so tired, no energy, headaches, I'm out of breath after walking three steps. I'm not sure what's going on but I do not feel myself. I do have chest pains but they are quick and then gone. Any suggestions would be great.