DEAR ERIC: I am in my 70s, and for the last couple of decades I have had occasional coughing fits that are triggered by talking too long and/or too loudly. When these fits happen, I literally can’t talk or stop coughing for several minutes. I’ve been to several doctors but have not been able to get a clear diagnosis or effective treatment. My closest family and friends understand the problem, but it’s still embarrassing, especially when it happens with people I don’t know well or in a public setting. When I am talking to others, should I warn them at the beginning of the conversation that I mi…