I've recently completed tests of my heart, lungs and blood. All were normal. However I continue to have severe shortness of breath with activity. Sitting or lying down I have no problem, but when walking, getting dressed or other activity I have shortness of breath and feel weak. I have been taking blood pressure medicine for many years. I currently take Lisinop/HCTZ 20/25 and my doctor added Amlodipine about 6 months go. I have also been taking Timolol Maleate Ophthalmic Solution 0.5% for about two years. The shortness of breath began about two years and has gotten worse over the past year. Today, I can walk only about a half block and must sit down and rest before continuing. My cardiologist and internal medicine doctor are puzzled. When I meet with them again next week my guess is they will want to conduct more tests. Is there a possibility that the combination of medicine I'm taking could be the cause?