I've been sick on and off for three months now! Please help! I need relief!?

Ok, so about 3 months ago I had a really bad cold. That cold then turned into the flu. The flu lasted for about 2 weeks and I was feeling better. A couple days after I was coughing really bad again. They said I had bronchitis (which lasted forever!). They put me on a "z-pac" and breathing treatments and also steroids. I was starting to feel better again and then a couple days ago I started coughing again. I have a really sore throat and severe abdominal pain. I am also having chest pains and shortness of breath. I am still taking my breathing treatments and they have already done tests and I don't have asthma. Please help! My grandmother has me worried that I have pneumonia. I just really need some advice!