I have LBBB with an EF of 25. I have been gradually ramping up on Coreg. I have reached 25 mg BID. I just started to get a tightness or pain in my sternum when I laugh or cough. This started about and hour or two ago. I'm familiar with heartburn and have a hiatal hernia that I take protonix for. I am wearing a diffibrilator life vest. Otherwise, I feel the same as I have. Should I be concerned or just wait until the morning to call my doctor.