Hi, I'm A 26 Yr. Old Female. 30 Lbs Overweight.

Hi, I'm a 26 yr. Old female. 30 lbs overweight. I have never smoked, done drugs, or drank alcohol. About 7 weeks ago I started with shortness of breath. Some days are worse than others but the problem doesn't seem to go away. I went to the Dr and she said I had anxiety and depression and prescribed paxil 20 mg. Which i'm scared to take because all the side affect. Recently like 4 days ago I started noticing when I take a deep breath I could feel a pop sound when I inhale deep. It seems to be behind my heart close to my spinal cord. I didn't tell the Dr. This being that it didn't happen when I went to the Dr. On the shortness of breath it seems like I'm breathing normal and i get the feeling that I'm not getting enough air. So I try and take a deep breath sometimes I'm able to get a nice and clean breath which feels great. But I notice that small pop sound. And others times that I'm stopped half way into the breath because I can't draw enough air in. I don't know what to do I feel so helpless this feeling is interfering with my day to day life. Please help.