Constant Deep Pressure In Chest, Congested. Reason? Cure?

I constantly have a deep pressure/ache in my chest, it feels as one might feel when they are getting a chest cold . I feel congested and feel like I m not getting enough air. The chest has a constant ache and it radiates into my back between my shoulder blades. Every so often I get a sharp stabbing pain in mid chest or in my back between my shoulder blades. I have had ever test done under the sun on my heart, and all results have come back normal. I have had chest xrays and PFT all normal as well. I have no quality of lift because I get so out of breath doing anything, even just taking a shower. I am only 44 years old, and live in fear everyday not knowing what s going on, and it scares me. I am exhausted from worrying about it. Any ideas would be greatly appreciated.