What Causes Allergic Wheezing And Soreness In The Chest?

Hi I am 61 year old woman who has never smoked or had lung problems. I have often wheezed when I laugh. When I walk up incline I often pant. My heart and blood pressure are fine. The last four days I have developed a wheeze and I don t cough a lot but when I do I wheeze. I went to doctor and she sent me for a lung X-ray and prescribed a puffer. She says it may be allergies and that she can hear some wheezing. I am worried it could be a form of lung cancer. Would problems show up on a regular chest X-ray? I dont have trouble breathing and my chest is not sore. The area that is affected appears to be just under the throat. I did notice a noise in my throat area as well as some sort of movement under the throat and then the wheezing started. there appears to be phlegm when I cough, but there is not much phlegm when I spit into a Kleenex. The phlegm doesn t break up Thanks Janice