How do you differentiate between copd and asthma? can stress on top of asthma, allergies, and panic attacks cause copd? i have trouble exhaling fully.

PFTs: You want to have lung function testing in a reputable lab. Check with your lung doc.

Reversibility: Asthma and COPD overlap however asthma shows reversible pft changes where the changes with COPD are more fixed. In addition COPD is a disease mostly of older people who have been smokers, asthma can affect anyone including young people and is often associated with a hx of allergies. In some patients the tow disease coexist. Stress/anxiety make both worse but do not "cause" copd.