I am experiencing fatigue, obesity, shortness of breath (time frame: gradual onset) (severity: mild) (worsened by: exercise or physical activity). .. activity-walking into a store in there about five minutes walking out, I was feeling very tired.?

Needs evaluation. This could be any number of things - and should be properly evaluated by a doctor with questioning (history), physical exam, labs and studies. The list of possible diseases is long, but hopefully as you point out relatively mild in presentation. If you can't get an appointment with your primary doctor right away, you might want to connect with a Health Tap doc here for a virtual consult.