Can asthma with 15 % of deficit of breathing get worse without treatment? i'm taking symbicort, (budesonide and formoterol) i'm healthy, but don't like to take meds..

Yes: At its base, asthma is an inflammatory problem of the lungs, & if you don't stay on your symbicort, (budesonide and formoterol) which contains an inhaled steroid to control the inflammation, it will get worse.

Yes....: If airway inflammation is allowed to continue untreated, the disease can worsen over time. So, you need to take your medicine today to avoid more serious sequelae later.