Started 10 mg Lisinopril, after 4 days I couldn't catch my breath...

Started 10 mg Lisinopril, after 4 days I couldn't catch my breath. Had to sit and not even talk, in order to get oxygen in. Couldn't sleep, would wake up gasping for air. Would take 2 breaths and the 3rd would be a yawn to get oxygen in. It's been 5 days since I quit taking Lisinopril, and my breathing finally feels normal. And the doctor said this is not a side effect of the drug, just a coincidence. In fairness, I have two friends who have been on it 15 and 20 years respectively. Also a 95 year old aunt, and she suffers from shortness of breath but blames it on other things. I wonder. A doctor at my health club said his patients have had great success with Resperate, a biofeedback machine, for blood pressure. Will give that a try next.