How Can Chronic Cough Be Treated?

Hi! Im 26 yrs old, female, & a singer and musician in my church and have been for around 12 years. I have no professional experience or training. I’ve always struggled with allergies and singing, but Awhile back I had whooping cough and I’ve never been the same since. It seems like I always have some coughing or other symptom going on. My doctor suspected I had walking pneumonia about 6 months ago and did a chest X-ray but it was clear so they just sent me home. I’ve never fully recovered. If I over exert my voice I lose it and start coughing and have trouble breathing. The last 2 weeks tho, I’ve started experiencing severe chest pains (only when I try to sing) and I can’t breathe. I’ve left the stage a few times and went and cried in the bath room because the pain was too much. It usually lingers the rest of the night and I feel better in the morning. Every church service I try to sing, it happens all over again. Throughout the course of a normal day I’m fine, it’s only when I sing. Any thoughts as to what exactly could be going on?