m no doctor, but I recently went through what you are going through. I have asthma as well and was on a
beta blocker, Toprol...it was horrible. It handled my high BP, but I absolutely could not breath..wheezing, coughing, tightness in the chest, all the standard asthma symptoms. My cardiologist changed me to a channel blocker (beta blockers are KNOWN to affect the bronchial tubes negatively) and I've had no problems since. I'm on Cartial XP.
Good Luck to you!