Suggest Treatment For Swollen Lymph Node And Irregular Heart Beats

Hi , I have just over the past week had a swollen lymph nobe on the left back side under my neck jaw. It s sore. I also suffer with a sliding hiatus hernia and take Nexium. I also lately have an irregular heart beat at times with a lump feeling in chest at the base of throat, I m a little worried, but recent blood test says blood count is normal, should I be worried, thanks