The reason why a sore throat occurs after a cold is because of the inflammation that occurs in the throat. A cold is an infection of the upper respiratory tract, including the nose, throat and pharynx, caused by a cold virus or bacteria. If inflammation occurs in the throat, it will be accompanied by congestion and edema, as well as redness, swelling, heat and pain. If you have a sore throat, it may be caused by a viral infection or a bacterial infection, or it may be caused by Mycoplasma pneumoniae or Chlamydia. 1. If a viral infection occurs, you can use Pudilan Anti-inflammatory Oral Liquid or Blue Scutellaria Oral Liquid for anti-inflammatory treatment to relieve a sore throat. 2. 3.If mycoplasma or chlamydia infection occurs, macrolide antibiotics should be used for treatment, the effect is better, such as oral azithromycin or roxithromycin.