What Causes Trouble Breathing With Severe Cough?

I’ve been having trouble breathing for the past two or three week, and in the last couple days it has just gotten worse. I feel the need to cough up phlegm, but my respiratory tract is dry and nothing comes up. It feels like there is a weigh on my chest, and I struggle to inhale. My chest and back sometimes hurt and I feel palpitations. I occasionally get lightheaded and have also been extremely thirsty in the past couple of days. I do have asthma and allergies, but none of the allergy medicine I have taken has helped much. Also, I’ve have cold spells, usually after eating lunch, that makes it worse. Is it just my asthma? Or is it something else? And should I be concerned? Is there anything I can take to relieve my symptoms?