Shortness of breathe: This can sometimes stem from intense exercise, extreme temperatures, high altitude, or obesity, but shortness of breath is typically one symptom to pay attention to. If this comes on suddenly and is pretty severe, call a doctor. Diseases can include: chronic obstructive pulmonary disease, asthma, bronchitis, pneumonia, blood clot in the lung, and heart or lung problems. Shortness of breath can also be triggered by a panic attack, which is a non-life threatening issue. Although there is no harm in going to the doctor even if it is a panic attack, you’d rather be safe than sorry when it comes to this symptom.