Hi and thank you so much for this query. I am so sorry to hear about this heartburn. Cymbalta is not typically known to cause heart bur, I will that you get this looked into as a possible reflux disease and managed accordingly. If antacids do not resolve the problem, then there may be need to try omeprazole and failure would prompt investigations like endoscopy to make sure there is nothing more to be concerned about. Try to avoid eating late, avoid fatty meals, chocolate, coffee, to help ease the symptoms. I hope you find this helpful. I wish you well and feel free to ask for more information and clarifications if need be. Dr. Ivo, MD.