1) either you are allergic to the material by which the capsules are made. try a different brand of HCl. go for a reputed one.
2) the capsules are not going down to the stomach and are getting stuck in the esophagus. this happened to me a few times when I took the capsules after the meal and they didn't go completely down to the stomach which caused burning in my chest and throat. now I take the capsules before the last 4-5 bites of the meal to make sure that they go down to the stomach.