I Have A Feeling In Upper Left Lung/chest Area That

I have a feeling in upper left lung/chest area that feels like a bubble that needs to pop. I have no issues walking around with breathing or anything like that. However, when I sit down or drive in my car I notice it more than when moving around. I've had no chest pain or coughing. Just the oocasional feeling I can't get a good breath when sitting and the bubble feeling that is happening often the past week. Any ideas?